Release 6.2.8

Require Locale argument for toLower/toUpperCase usage
Bump io.micrometer:micrometer-observation from 1.12.12 to 1.12.13
2026-07-08 12:20:02 +00:00 · 2024-11-18 15:23:13 +00:00 · 2024-11-18 04:22:26 -05:00 · 2024-11-17 19:53:46 -08:00 · 2024-11-17 19:51:06 -08:00 · 2024-11-17 16:59:03 -08:00
80 changed files with 2722 additions and 361 deletions
@@ -113,20 +113,13 @@ jobs:
      artifact-path: org/springframework/security/spring-security-core
      slack-announcing-id: spring-security-announcing
    secrets: inherit
-  notify_result:
-    name: Check for failures
+  send-notification:
+    name: Send Notification
    needs: [ perform-release ]
-    if: failure()
+    if: ${{ failure() || cancelled() }}
    runs-on: ubuntu-latest
-    permissions:
-      actions: read
    steps:
-      - name: Send Slack message
-        # Workaround while waiting for Gamesight/slack-workflow-status#38 to be fixed
-        # See https://github.com/Gamesight/slack-workflow-status/issues/38
-        uses: sjohnr/slack-workflow-status@v1-beta
+      - name: Send Notification
+        uses: spring-io/spring-security-release-tools/.github/actions/send-notification@v1
        with:
-          repo_token: ${{ secrets.GITHUB_TOKEN }}
-          slack_webhook_url: ${{ secrets.SLACK_WEBHOOK_URL }}
-          channel: '#spring-security-ci'
-          name: 'CI Notifier'
+          webhook-url: ${{ secrets.SPRING_SECURITY_CI_GCHAT_WEBHOOK_URL }}
@@ -22,10 +22,9 @@ jobs:
      - name: Find PRs
        id: find_duplicates
        env:
-          DEPENDENCY_NAME: ${{ steps.extract.outputs.dependency_name }}
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
-          PRS=$(gh pr list --search 'milestone:${{ github.event.pull_request.milestone.title }} is:merged in:title "$DEPENDENCY_NAME"' --json number --jq 'map(.number) | join(",")')
+          PRS=$(gh pr list --search 'milestone:${{ github.event.pull_request.milestone.title }} is:merged in:title "${{ steps.extract.outputs.dependency_name }}"' --json number --jq 'map(.number) | join(",")')
          echo "prs=$PRS" >> $GITHUB_OUTPUT

      - name: Label Duplicate PRs
@@ -8,6 +8,7 @@ permissions: write-all

 jobs:
  merge-dependabot-pr:
+    name: Merge Dependabot PR
    runs-on: ubuntu-latest
    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' && github.repository == 'spring-projects/spring-security' }}
    steps:
@@ -50,3 +51,13 @@ jobs:
        run: gh pr merge ${{ github.event.pull_request.number }} --auto --rebase
        env:
          GH_TOKEN: ${{ secrets.GH_ACTIONS_REPO_TOKEN }}
+  send-notification:
+    name: Send Notification
+    needs: [ merge-dependabot-pr ]
+    if: ${{ failure() || cancelled() }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Send Notification
+        uses: spring-io/spring-security-release-tools/.github/actions/send-notification@v1
+        with:
+          webhook-url: ${{ secrets.SPRING_SECURITY_CI_GCHAT_WEBHOOK_URL }}
@@ -23,18 +23,13 @@ jobs:
        export TOOL_VERSION=0.1.1
        wget "https://repo.maven.apache.org/maven2/io/spring/releasetrain/spring-release-train-tools/$TOOL_VERSION/spring-release-train-tools-$TOOL_VERSION.jar"
        java -cp "spring-release-train-tools-$TOOL_VERSION.jar" io.spring.releasetrain.CheckMilestoneDueOnMain --dueOn "$DUE_ON" --expectedDayOfWeek MONDAY --expectedMondayCount 3
-  notify_result:
-    name: Check for failures
-    needs: [spring-releasetrain-checks]
-    if: failure()
+  send-notification:
+    name: Send Notification
+    needs: [ spring-releasetrain-checks ]
+    if: ${{ failure() || cancelled() }}
    runs-on: ubuntu-latest
-    permissions:
-      actions: read
    steps:
-      - name: Send Slack message
-        uses: Gamesight/slack-workflow-status@v1.3.0
+      - name: Send Notification
+        uses: spring-io/spring-security-release-tools/.github/actions/send-notification@v1
        with:
-          repo_token: ${{ secrets.GITHUB_TOKEN }}
-          slack_webhook_url: ${{ secrets.SLACK_WEBHOOK_URL }}
-          channel: '#spring-security-ci'
-          name: 'CI Notifier'
+          webhook-url: ${{ secrets.SPRING_SECURITY_CI_GCHAT_WEBHOOK_URL }}
@@ -42,3 +42,13 @@ jobs:
          name: docs
          path: docs/build/site
          overwrite: true
+  send-notification:
+    name: Send Notification
+    needs: [ build, generate-docs ]
+    if: ${{ failure() && github.event.pull_request.user.login == 'dependabot[bot]' && github.repository == 'spring-projects/spring-security' }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Send Notification
+        uses: spring-io/spring-security-release-tools/.github/actions/send-notification@v1
+        with:
+          webhook-url: ${{ secrets.SPRING_SECURITY_CI_GCHAT_WEBHOOK_URL }}
@@ -11,3 +11,13 @@ jobs:
    name: Update Scheduled Release Version
    uses: spring-io/spring-security-release-tools/.github/workflows/update-scheduled-release-version.yml@v1
    secrets: inherit
+  send-notification:
+    name: Send Notification
+    needs: [ update-scheduled-release-version ]
+    if: ${{ failure() || cancelled() }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Send Notification
+        uses: spring-io/spring-security-release-tools/.github/actions/send-notification@v1
+        with:
+          webhook-url: ${{ secrets.SPRING_SECURITY_CI_GCHAT_WEBHOOK_URL }}
@@ -63,6 +63,7 @@ class EclipsePlugin implements Plugin<Project> {
 						// test sources. Relax those from error to warning
 						properties['org.eclipse.jdt.core.circularClasspath'] = 'warning'
 						properties['org.eclipse.jdt.core.incompleteClasspath'] = 'warning'
+						properties['org.eclipse.jdt.core.compiler.codegen.methodParameters'] = 'generate'
 					}
 				}
 			}
@@ -16,15 +16,23 @@

 package org.springframework.security;

-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-
 import org.gradle.api.DefaultTask;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.api.Task;
+import org.gradle.api.file.RegularFileProperty;
 import org.gradle.api.plugins.JavaBasePlugin;
+import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.CacheableTask;
+import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.OutputFile;
 import org.gradle.api.tasks.TaskAction;
+import org.gradle.api.tasks.TaskExecutionException;
 import org.gradle.api.tasks.TaskProvider;
+import org.gradle.api.tasks.VerificationException;
+
+import java.io.IOException;
+import java.nio.file.Files;

 /**
 * @author Marcus da Coregio
@@ -36,38 +44,60 @@ public class CheckExpectedBranchVersionPlugin implements Plugin<Project> {
 		TaskProvider<CheckExpectedBranchVersionTask> checkExpectedBranchVersionTask = project.getTasks().register("checkExpectedBranchVersion", CheckExpectedBranchVersionTask.class, (task) -> {
 			task.setGroup("Build");
 			task.setDescription("Check if the project version matches the branch version");
+			task.onlyIf("skipCheckExpectedBranchVersion property is false or not present", CheckExpectedBranchVersionPlugin::skipPropertyFalseOrNotPresent);
+			task.getVersion().convention(project.provider(() -> project.getVersion().toString()));
+			task.getBranchName().convention(project.getProviders().exec(execSpec -> execSpec.setCommandLine("git", "symbolic-ref", "--short", "HEAD")).getStandardOutput().getAsText());
+			task.getOutputFile().convention(project.getLayout().getBuildDirectory().file("check-expected-branch-version"));
 		});
 		project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME, checkTask -> checkTask.dependsOn(checkExpectedBranchVersionTask));
 	}

-	public static class CheckExpectedBranchVersionTask extends DefaultTask {
+	private static boolean skipPropertyFalseOrNotPresent(Task task) {
+		return task.getProject()
+				.getProviders()
+				.gradleProperty("skipCheckExpectedBranchVersion")
+				.orElse("false")
+				.map("false"::equalsIgnoreCase)
+				.get();
+	}
+
+	@CacheableTask
+	public static abstract class CheckExpectedBranchVersionTask extends DefaultTask {
+
+		@Input
+		abstract Property<String> getVersion();
+
+		@Input
+		abstract Property<String> getBranchName();
+
+		@OutputFile
+		abstract RegularFileProperty getOutputFile();

 		@TaskAction
-		public void run() throws IOException {
-			Project project = getProject();
-			if (project.hasProperty("skipCheckExpectedBranchVersion")) {
-				return;
-			}
-			String version = (String) project.getVersion();
-			String branchVersion = getBranchVersion(project);
+		public void run() {
+			String version = getVersion().get();
+			String branchVersion = getBranchName().map(String::trim).get();
 			if (!branchVersion.matches("^[0-9]+\\.[0-9]+\\.x$")) {
-				System.out.println("Branch version does not match *.x, ignoring");
+				String msg = String.format("Branch version [%s] does not match *.x, ignoring", branchVersion);
+				getLogger().warn(msg);
+				writeExpectedVersionOutput(msg);
 				return;
 			}
 			if (!versionsMatch(version, branchVersion)) {
-				throw new IllegalStateException(String.format("Project version [%s] does not match branch version [%s]. " +
-						"Please verify that the branch contains the right version.", version, branchVersion));
+				String msg = String.format("Project version [%s] does not match branch version [%s]. " +
+						"Please verify that the branch contains the right version.", version, branchVersion);
+				writeExpectedVersionOutput(msg);
+				throw new VerificationException(msg);
 			}
+
+			writeExpectedVersionOutput(version);
 		}

-		private static String getBranchVersion(Project project) throws IOException {
-			try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
-				project.exec((exec) -> {
-					exec.commandLine("git", "symbolic-ref", "--short", "HEAD");
-					exec.setErrorOutput(System.err);
-					exec.setStandardOutput(baos);
-				});
-				return baos.toString();
+		private void writeExpectedVersionOutput(String fileContent) {
+			try {
+				Files.writeString(getOutputFile().get().getAsFile().toPath(), fileContent);
+			} catch (IOException e) {
+				throw new TaskExecutionException(this, e);
 			}
 		}

@@ -19,52 +19,81 @@ package org.springframework.security.convention.versions;
 import org.gradle.api.DefaultTask;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.api.artifacts.Dependency;
 import org.gradle.api.artifacts.MinimalExternalModuleDependency;
 import org.gradle.api.artifacts.VersionCatalog;
 import org.gradle.api.artifacts.VersionCatalogsExtension;
+import org.gradle.api.file.RegularFile;
+import org.gradle.api.file.RegularFileProperty;
 import org.gradle.api.plugins.JavaBasePlugin;
+import org.gradle.api.provider.Property;
+import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.CacheableTask;
+import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.OutputFile;
 import org.gradle.api.tasks.TaskAction;
+import org.gradle.api.tasks.TaskExecutionException;
 import org.gradle.api.tasks.TaskProvider;
+import org.gradle.api.tasks.VerificationException;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.Optional;

 public class VerifyDependenciesVersionsPlugin implements Plugin<Project> {

 	@Override
 	public void apply(Project project) {
+		VersionCatalog versionCatalog = project.getExtensions().getByType(VersionCatalogsExtension.class).named("libs");
+		Optional<Provider<MinimalExternalModuleDependency>> oauth2OidcSdk = versionCatalog.findLibrary("com-nimbusds-oauth2-oidc-sdk");
+		Optional<Provider<MinimalExternalModuleDependency>> nimbusJoseJwt = versionCatalog.findLibrary("com-nimbusds-nimbus-jose-jwt");
+
+		if (oauth2OidcSdk.isEmpty()) {
+			throw new VerificationException("Library [com-nimbusds-oauth2-oidc-sdk] does not exist in the version catalog named libs.");
+		}
+
+		if (nimbusJoseJwt.isEmpty()) {
+			throw new VerificationException("Library [com-nimbusds-nimbus-jose-jwt] does not exist in the version catalog named libs.");
+		}
+
 		TaskProvider<VerifyDependenciesVersionsTask> verifyDependenciesVersionsTaskProvider = project.getTasks().register("verifyDependenciesVersions", VerifyDependenciesVersionsTask.class, (task) -> {
 			task.setGroup("Verification");
 			task.setDescription("Verify that specific dependencies are using the same version");
-			VersionCatalog versionCatalog = project.getExtensions().getByType(VersionCatalogsExtension.class).named("libs");
-			MinimalExternalModuleDependency oauth2OidcSdk = versionCatalog.findLibrary("com-nimbusds-oauth2-oidc-sdk").get().get();
-			MinimalExternalModuleDependency nimbusJoseJwt = versionCatalog.findLibrary("com-nimbusds-nimbus-jose-jwt").get().get();
-			task.setOauth2OidcSdkVersion(oauth2OidcSdk.getVersion());
-			task.setExpectedNimbusJoseJwtVersion(nimbusJoseJwt.getVersion());
+			task.getOauth2OidcSdkVersion().convention(oauth2OidcSdk.get().map(Dependency::getVersion));
+			task.getExpectedNimbusJoseJwtVersion().convention(nimbusJoseJwt.get().map(Dependency::getVersion));
+			task.getOutputFile().convention(project.getLayout().getBuildDirectory().file("verify-dependencies-versions"));
 		});
 		project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME, checkTask -> checkTask.dependsOn(verifyDependenciesVersionsTaskProvider));
 	}

-	public static class VerifyDependenciesVersionsTask extends DefaultTask {
+	@CacheableTask
+	public abstract static class VerifyDependenciesVersionsTask extends DefaultTask {

-		private String oauth2OidcSdkVersion;
+		@Input
+		abstract Property<String> getOauth2OidcSdkVersion();

-		private String expectedNimbusJoseJwtVersion;
+		@Input
+		abstract Property<String> getExpectedNimbusJoseJwtVersion();

-		public void setOauth2OidcSdkVersion(String oauth2OidcSdkVersion) {
-			this.oauth2OidcSdkVersion = oauth2OidcSdkVersion;
-		}
-
-		public void setExpectedNimbusJoseJwtVersion(String expectedNimbusJoseJwtVersion) {
-			this.expectedNimbusJoseJwtVersion = expectedNimbusJoseJwtVersion;
-		}
+		@OutputFile
+		abstract RegularFileProperty getOutputFile();

 		@TaskAction
-		public void verify() {
-			String transitiveNimbusJoseJwtVersion = TransitiveDependencyLookupUtils.lookupJwtVersion(this.oauth2OidcSdkVersion);
-			if (!transitiveNimbusJoseJwtVersion.equals(this.expectedNimbusJoseJwtVersion)) {
-				String message = String.format("Found transitive nimbus-jose-jwt:%s in oauth2-oidc-sdk:%s, but the project contains a different version of nimbus-jose-jwt [%s]. Please align the versions.", transitiveNimbusJoseJwtVersion, this.oauth2OidcSdkVersion, this.expectedNimbusJoseJwtVersion);
-				throw new IllegalStateException(message);
+		public void verify()  {
+			String oauth2OidcSdkVersion = this.getOauth2OidcSdkVersion().get();
+			String transitiveNimbusJoseJwtVersion = TransitiveDependencyLookupUtils.lookupJwtVersion(oauth2OidcSdkVersion);
+			String expectedNimbusJoseJwtVersion = this.getExpectedNimbusJoseJwtVersion().get();
+			if (!transitiveNimbusJoseJwtVersion.equals(expectedNimbusJoseJwtVersion)) {
+				String message = String.format("Found transitive nimbus-jose-jwt:%s in oauth2-oidc-sdk:%s, but the project contains a different version of nimbus-jose-jwt [%s]. Please align the versions.", transitiveNimbusJoseJwtVersion, oauth2OidcSdkVersion, expectedNimbusJoseJwtVersion);
+				throw new VerificationException(message);
+			}
+			String message = String.format("Found transitive nimbus-jose-jwt:%s in oauth2-oidc-sdk:%s, the project contains expected version of nimbus-jose-jwt [%s]. Verified all versions align.", transitiveNimbusJoseJwtVersion, oauth2OidcSdkVersion, expectedNimbusJoseJwtVersion);
+			try {
+				Files.writeString(getOutputFile().get().getAsFile().toPath(), message);
+			} catch (IOException e) {
+				throw new TaskExecutionException(this, e);
 			}
 		}
-
 	}
-
 }
@@ -18,6 +18,7 @@ package org.springframework.security.cas.userdetails;

 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;

 import org.apereo.cas.client.validation.Assertion;

@@ -73,7 +74,8 @@ public final class GrantedAuthorityFromAssertionAttributesUserDetailsService
 	}

 	private SimpleGrantedAuthority createSimpleGrantedAuthority(Object o) {
-		return new SimpleGrantedAuthority(this.convertToUpperCase ? o.toString().toUpperCase() : o.toString());
+		return new SimpleGrantedAuthority(
+				this.convertToUpperCase ? o.toString().toUpperCase(Locale.ROOT) : o.toString());
 	}

 	/**
@@ -509,7 +509,8 @@ public abstract class AbstractRequestMatcherRegistry<C> {
 		public boolean matches(HttpServletRequest request) {
 			String name = request.getHttpServletMapping().getServletName();
 			ServletRegistration registration = this.servletContext.getServletRegistration(name);
-			Assert.notNull(registration, computeErrorMessage(this.servletContext.getServletRegistrations().values()));
+			Assert.notNull(registration,
+					() -> computeErrorMessage(this.servletContext.getServletRegistrations().values()));
 			try {
 				Class<?> clazz = Class.forName(registration.getClassName());
 				return DispatcherServlet.class.isAssignableFrom(clazz);
@@ -171,7 +171,8 @@ public final class AuthorizeHttpRequestsConfigurer<H extends HttpSecurityBuilder
 			Assert.state(this.mappingCount > 0,
 					"At least one mapping is required (for example, authorizeHttpRequests().anyRequest().authenticated())");
 			ObservationRegistry registry = getObservationRegistry();
-			RequestMatcherDelegatingAuthorizationManager manager = postProcess(this.managerBuilder.build());
+			AuthorizationManager<HttpServletRequest> manager = postProcess(
+					(AuthorizationManager<HttpServletRequest>) this.managerBuilder.build());
 			if (registry.isNoop()) {
 				return manager;
 			}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@ import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
 import org.springframework.security.oauth2.core.OAuth2TokenValidator;
 import org.springframework.security.oauth2.core.OAuth2TokenValidatorResult;
 import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.util.Assert;

 /**
 * A {@link OAuth2TokenValidator} that validates OIDC Logout Token claims in conformance
@@ -57,7 +58,9 @@ final class OidcBackChannelLogoutTokenValidator implements OAuth2TokenValidator<

 	OidcBackChannelLogoutTokenValidator(ClientRegistration clientRegistration) {
 		this.audience = clientRegistration.getClientId();
-		this.issuer = clientRegistration.getProviderDetails().getIssuerUri();
+		String issuer = clientRegistration.getProviderDetails().getIssuerUri();
+		Assert.hasText(issuer, "Provider issuer cannot be null");
+		this.issuer = issuer;
 	}

 	@Override
@@ -21,6 +21,7 @@ import java.util.List;

 import io.micrometer.observation.ObservationRegistry;

+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
 import org.springframework.context.ApplicationContext;
@@ -33,6 +34,8 @@ import org.springframework.security.web.reactive.result.view.CsrfRequestDataValu
 import org.springframework.security.web.server.ObservationWebFilterChainDecorator;
 import org.springframework.security.web.server.SecurityWebFilterChain;
 import org.springframework.security.web.server.WebFilterChainProxy;
+import org.springframework.security.web.server.firewall.ServerExchangeRejectedHandler;
+import org.springframework.security.web.server.firewall.ServerWebExchangeFirewall;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.web.reactive.result.view.AbstractView;
@@ -79,11 +82,14 @@ class WebFluxSecurityConfiguration {

 	@Bean(SPRING_SECURITY_WEBFILTERCHAINFILTER_BEAN_NAME)
 	@Order(WEB_FILTER_CHAIN_FILTER_ORDER)
-	WebFilterChainProxy springSecurityWebFilterChainFilter() {
+	WebFilterChainProxy springSecurityWebFilterChainFilter(ObjectProvider<ServerWebExchangeFirewall> firewall,
+			ObjectProvider<ServerExchangeRejectedHandler> rejectedHandler) {
 		WebFilterChainProxy proxy = new WebFilterChainProxy(getSecurityWebFilterChains());
 		if (!this.observationRegistry.isNoop()) {
 			proxy.setFilterChainDecorator(new ObservationWebFilterChainDecorator(this.observationRegistry));
 		}
+		firewall.ifUnique(proxy::setFirewall);
+		rejectedHandler.ifUnique(proxy::setExchangeRejectedHandler);
 		return proxy;
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.config.http;

 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;

 import io.micrometer.observation.ObservationRegistry;
 import jakarta.servlet.ServletRequest;
@@ -313,7 +314,7 @@ class HttpConfigurationBuilder {

 	// Needed to account for placeholders
 	static String createPath(String path, boolean lowerCase) {
-		return lowerCase ? path.toLowerCase() : path;
+		return lowerCase ? path.toLowerCase(Locale.ENGLISH) : path;
 	}

 	BeanMetadataElement getSecurityContextHolderStrategyForAuthenticationFilters() {
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@ import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
 import org.springframework.security.oauth2.core.OAuth2TokenValidator;
 import org.springframework.security.oauth2.core.OAuth2TokenValidatorResult;
 import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.util.Assert;

 /**
 * A {@link OAuth2TokenValidator} that validates OIDC Logout Token claims in conformance
@@ -57,7 +58,9 @@ final class OidcBackChannelLogoutTokenValidator implements OAuth2TokenValidator<

 	OidcBackChannelLogoutTokenValidator(ClientRegistration clientRegistration) {
 		this.audience = clientRegistration.getClientId();
-		this.issuer = clientRegistration.getProviderDetails().getIssuerUri();
+		String issuer = clientRegistration.getProviderDetails().getIssuerUri();
+		Assert.hasText(issuer, "Provider issuer cannot be null");
+		this.issuer = issuer;
 	}

 	@Override
@@ -73,6 +73,8 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;

 /**
@@ -447,6 +449,18 @@ public class PrePostMethodSecurityConfigurationTests {
 			.autowire();
 	}

+	// gh-15651
+	@Test
+	@WithMockUser(roles = "ADMIN")
+	public void adviseWhenPrePostEnabledThenEachInterceptorRunsExactlyOnce() {
+		this.spring.register(MethodSecurityServiceConfig.class, CustomMethodSecurityExpressionHandlerConfig.class)
+			.autowire();
+		MethodSecurityExpressionHandler expressionHandler = this.spring.getContext()
+			.getBean(MethodSecurityExpressionHandler.class);
+		this.methodSecurityService.manyAnnotations(new ArrayList<>(Arrays.asList("harold", "jonathan", "tim", "bo")));
+		verify(expressionHandler, times(4)).createEvaluationContext(any(Supplier.class), any());
+	}
+
 	private static Consumer<ConfigurableWebApplicationContext> disallowBeanOverriding() {
 		return (context) -> ((AnnotationConfigWebApplicationContext) context).setAllowBeanDefinitionOverriding(false);
 	}
@@ -523,6 +537,19 @@ public class PrePostMethodSecurityConfigurationTests {
 	}

 	@Configuration
+	@EnableMethodSecurity
+	static class CustomMethodSecurityExpressionHandlerConfig {
+
+		private final MethodSecurityExpressionHandler expressionHandler = spy(
+				new DefaultMethodSecurityExpressionHandler());
+
+		@Bean
+		MethodSecurityExpressionHandler methodSecurityExpressionHandler() {
+			return this.expressionHandler;
+		}
+
+	}
+
 	@EnableMethodSecurity
 	static class CustomPermissionEvaluatorConfig {

@@ -153,6 +153,7 @@ public class AuthorizeHttpRequestsConfigurerTests {
 		this.spring.register(ObjectPostProcessorConfig.class).autowire();
 		ObjectPostProcessor objectPostProcessor = this.spring.getContext().getBean(ObjectPostProcessor.class);
 		verify(objectPostProcessor).postProcess(any(RequestMatcherDelegatingAuthorizationManager.class));
+		verify(objectPostProcessor).postProcess(any(AuthorizationManager.class));
 		verify(objectPostProcessor).postProcess(any(AuthorizationFilter.class));
 	}

@@ -650,7 +650,7 @@ public class OAuth2LoginConfigurerTests {
 	}

 	@Test
-	public void configureWhenOidcSessionStrategyThenUses() {
+	public void configureWhenOidcSessionRegistryThenUses() {
 		this.spring.register(OAuth2LoginWithOidcSessionRegistry.class).autowire();
 		OidcSessionRegistry registry = this.spring.getContext().getBean(OidcSessionRegistry.class);
 		this.spring.getContext().publishEvent(new HttpSessionDestroyedEvent(this.request.getSession()));
@@ -91,6 +91,7 @@ import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;

+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.hamcrest.Matchers.containsString;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.willThrow;
@@ -259,6 +260,22 @@ public class OidcLogoutConfigurerTests {
 		verify(sessionRegistry).removeSessionInformation(any(OidcLogoutToken.class));
 	}

+	@Test
+	void logoutWhenProviderIssuerMissingThenThrowIllegalArgumentException() throws Exception {
+		this.spring.register(WebServerConfig.class, OidcProviderConfig.class, ProviderIssuerMissingConfig.class)
+			.autowire();
+		String registrationId = this.clientRegistration.getRegistrationId();
+		MockHttpSession session = login();
+		String logoutToken = this.mvc.perform(get("/token/logout").session(session))
+			.andExpect(status().isOk())
+			.andReturn()
+			.getResponse()
+			.getContentAsString();
+		assertThatIllegalArgumentException().isThrownBy(
+				() -> this.mvc.perform(post(this.web.url("/logout/connect/back-channel/" + registrationId).toString())
+					.param("logout_token", logoutToken)));
+	}
+
 	private MockHttpSession login() throws Exception {
 		MockMvcDispatcher dispatcher = (MockMvcDispatcher) this.web.getDispatcher();
 		this.mvc.perform(get("/token/logout")).andExpect(status().isUnauthorized());
@@ -410,6 +427,54 @@ public class OidcLogoutConfigurerTests {

 	}

+	@Configuration
+	static class ProviderIssuerMissingRegistrationConfig {
+
+		@Autowired(required = false)
+		MockWebServer web;
+
+		@Bean
+		ClientRegistration clientRegistration() {
+			if (this.web == null) {
+				return TestClientRegistrations.clientRegistration().issuerUri(null).build();
+			}
+			String issuer = this.web.url("/").toString();
+			return TestClientRegistrations.clientRegistration()
+				.issuerUri(null)
+				.jwkSetUri(issuer + "jwks")
+				.tokenUri(issuer + "token")
+				.userInfoUri(issuer + "user")
+				.scope("openid")
+				.build();
+		}
+
+		@Bean
+		ClientRegistrationRepository clientRegistrationRepository(ClientRegistration clientRegistration) {
+			return new InMemoryClientRegistrationRepository(clientRegistration);
+		}
+
+	}
+
+	@Configuration
+	@EnableWebSecurity
+	@Import(ProviderIssuerMissingRegistrationConfig.class)
+	static class ProviderIssuerMissingConfig {
+
+		@Bean
+		@Order(1)
+		SecurityFilterChain filters(HttpSecurity http) throws Exception {
+			// @formatter:off
+			http
+					.authorizeHttpRequests((authorize) -> authorize.anyRequest().authenticated())
+					.oauth2Login(Customizer.withDefaults())
+					.oidcLogout((oidc) -> oidc.backChannel(Customizer.withDefaults()));
+			// @formatter:on
+
+			return http.build();
+		}
+
+	}
+
 	@Configuration
 	@EnableWebSecurity
 	@EnableWebMvc
@@ -448,6 +513,9 @@ public class OidcLogoutConfigurerTests {
 		@Autowired
 		ClientRegistration registration;

+		@Autowired(required = false)
+		MockWebServer web;
+
 		@Bean
 		@Order(0)
 		SecurityFilterChain authorizationServer(HttpSecurity http, ClientRegistration registration) throws Exception {
@@ -484,7 +552,7 @@ public class OidcLogoutConfigurerTests {
 			HttpSession session = request.getSession();
 			JwtEncoderParameters parameters = JwtEncoderParameters
 					.from(JwtClaimsSet.builder().id("id").subject(this.username)
-							.issuer(this.registration.getProviderDetails().getIssuerUri()).issuedAt(Instant.now())
+							.issuer(getIssuerUri()).issuedAt(Instant.now())
 							.expiresAt(Instant.now().plusSeconds(86400)).claim("scope", "openid").build());
 			String token = this.encoder.encode(parameters).getTokenValue();
 			return new OIDCTokens(idToken(session.getId()), new BearerAccessToken(token, 86400, new Scope("openid")), null)
@@ -492,7 +560,7 @@ public class OidcLogoutConfigurerTests {
 		}

 		String idToken(String sessionId) {
-			OidcIdToken token = TestOidcIdTokens.idToken().issuer(this.registration.getProviderDetails().getIssuerUri())
+			OidcIdToken token = TestOidcIdTokens.idToken().issuer(getIssuerUri())
 					.subject(this.username).expiresAt(Instant.now().plusSeconds(86400))
 					.audience(List.of(this.registration.getClientId())).nonce(this.nonce)
 					.claim(LogoutTokenClaimNames.SID, sessionId).build();
@@ -501,6 +569,13 @@ public class OidcLogoutConfigurerTests {
 			return this.encoder.encode(parameters).getTokenValue();
 		}

+		private String getIssuerUri() {
+			if (this.web == null) {
+				return TestClientRegistrations.clientRegistration().build().getProviderDetails().getIssuerUri();
+			}
+			return this.web.url("/").toString();
+		}
+
 		@GetMapping("/user")
 		Map<String, Object> userinfo() {
 			return Map.of("sub", this.username, "id", this.username);
@@ -16,14 +16,26 @@

 package org.springframework.security.config.annotation.web.reactive;

+import java.util.Collections;
+
+import org.jetbrains.annotations.NotNull;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import reactor.core.publisher.Mono;

+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpStatus;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.web.server.MockServerWebExchange;
 import org.springframework.security.config.test.SpringTestContext;
 import org.springframework.security.config.test.SpringTestContextExtension;
 import org.springframework.security.config.users.ReactiveAuthenticationTestConfiguration;
 import org.springframework.security.web.server.WebFilterChainProxy;
+import org.springframework.security.web.server.firewall.HttpStatusExchangeRejectedHandler;
+import org.springframework.security.web.server.firewall.ServerExchangeRejectedHandler;
+import org.springframework.security.web.server.firewall.ServerWebExchangeFirewall;
+import org.springframework.web.server.handler.DefaultWebFilterChain;

 import static org.assertj.core.api.Assertions.assertThat;

@@ -47,6 +59,46 @@ public class WebFluxSecurityConfigurationTests {
 		assertThat(webFilterChainProxy).isNotNull();
 	}

+	@Test
+	void loadConfigWhenDefaultThenFirewalled() throws Exception {
+		this.spring
+			.register(ServerHttpSecurityConfiguration.class, ReactiveAuthenticationTestConfiguration.class,
+					WebFluxSecurityConfiguration.class)
+			.autowire();
+		WebFilterChainProxy webFilterChainProxy = this.spring.getContext().getBean(WebFilterChainProxy.class);
+		MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("/;/").build());
+		DefaultWebFilterChain chain = emptyChain();
+		webFilterChainProxy.filter(exchange, chain).block();
+		assertThat(exchange.getResponse().getStatusCode()).isEqualTo(HttpStatus.BAD_REQUEST);
+	}
+
+	@Test
+	void loadConfigWhenCustomRejectedHandler() throws Exception {
+		this.spring
+			.register(ServerHttpSecurityConfiguration.class, ReactiveAuthenticationTestConfiguration.class,
+					WebFluxSecurityConfiguration.class, CustomServerExchangeRejectedHandlerConfig.class)
+			.autowire();
+		WebFilterChainProxy webFilterChainProxy = this.spring.getContext().getBean(WebFilterChainProxy.class);
+		MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("/;/").build());
+		DefaultWebFilterChain chain = emptyChain();
+		webFilterChainProxy.filter(exchange, chain).block();
+		assertThat(exchange.getResponse().getStatusCode())
+			.isEqualTo(CustomServerExchangeRejectedHandlerConfig.EXPECTED_STATUS);
+	}
+
+	@Test
+	void loadConfigWhenFirewallBeanThenCustomized() throws Exception {
+		this.spring
+			.register(ServerHttpSecurityConfiguration.class, ReactiveAuthenticationTestConfiguration.class,
+					WebFluxSecurityConfiguration.class, NoOpFirewallConfig.class)
+			.autowire();
+		WebFilterChainProxy webFilterChainProxy = this.spring.getContext().getBean(WebFilterChainProxy.class);
+		MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("/;/").build());
+		DefaultWebFilterChain chain = emptyChain();
+		webFilterChainProxy.filter(exchange, chain).block();
+		assertThat(exchange.getResponse().getStatusCode()).isNotEqualTo(HttpStatus.BAD_REQUEST);
+	}
+
 	@Test
 	public void loadConfigWhenBeanProxyingEnabledAndSubclassThenWebFilterChainProxyExists() {
 		this.spring
@@ -57,6 +109,32 @@ public class WebFluxSecurityConfigurationTests {
 		assertThat(webFilterChainProxy).isNotNull();
 	}

+	private static @NotNull DefaultWebFilterChain emptyChain() {
+		return new DefaultWebFilterChain((webExchange) -> Mono.empty(), Collections.emptyList());
+	}
+
+	@Configuration
+	static class NoOpFirewallConfig {
+
+		@Bean
+		ServerWebExchangeFirewall noOpFirewall() {
+			return ServerWebExchangeFirewall.INSECURE_NOOP;
+		}
+
+	}
+
+	@Configuration
+	static class CustomServerExchangeRejectedHandlerConfig {
+
+		static HttpStatus EXPECTED_STATUS = HttpStatus.I_AM_A_TEAPOT;
+
+		@Bean
+		ServerExchangeRejectedHandler rejectedHandler() {
+			return new HttpStatusExchangeRejectedHandler(EXPECTED_STATUS);
+		}
+
+	}
+
 	@Configuration
 	static class SubclassConfig extends WebFluxSecurityConfiguration {

@@ -323,6 +323,30 @@ public class OidcLogoutSpecTests {
 		verify(sessionRegistry, atLeastOnce()).removeSessionInformation(any(OidcLogoutToken.class));
 	}

+	@Test
+	void logoutWhenProviderIssuerMissingThen5xxServerError() {
+		this.spring.register(WebServerConfig.class, OidcProviderConfig.class, ProviderIssuerMissingConfig.class)
+			.autowire();
+		String registrationId = this.clientRegistration.getRegistrationId();
+		String session = login();
+		String logoutToken = this.test.mutateWith(session(session))
+			.get()
+			.uri("/token/logout")
+			.exchange()
+			.expectStatus()
+			.isOk()
+			.returnResult(String.class)
+			.getResponseBody()
+			.blockFirst();
+		this.test.post()
+			.uri(this.web.url("/logout/connect/back-channel/" + registrationId).toString())
+			.body(BodyInserters.fromFormData("logout_token", logoutToken))
+			.exchange()
+			.expectStatus()
+			.is5xxServerError();
+		this.test.mutateWith(session(session)).get().uri("/token/logout").exchange().expectStatus().isOk();
+	}
+
 	private String login() {
 		this.test.get().uri("/token/logout").exchange().expectStatus().isUnauthorized();
 		String registrationId = this.clientRegistration.getRegistrationId();
@@ -499,6 +523,54 @@ public class OidcLogoutSpecTests {

 	}

+	@Configuration
+	static class ProviderIssuerMissingRegistrationConfig {
+
+		@Autowired(required = false)
+		MockWebServer web;
+
+		@Bean
+		ClientRegistration clientRegistration() {
+			if (this.web == null) {
+				return TestClientRegistrations.clientRegistration().issuerUri(null).build();
+			}
+			String issuer = this.web.url("/").toString();
+			return TestClientRegistrations.clientRegistration()
+				.issuerUri(null)
+				.jwkSetUri(issuer + "jwks")
+				.tokenUri(issuer + "token")
+				.userInfoUri(issuer + "user")
+				.scope("openid")
+				.build();
+		}
+
+		@Bean
+		ReactiveClientRegistrationRepository clientRegistrationRepository(ClientRegistration clientRegistration) {
+			return new InMemoryReactiveClientRegistrationRepository(clientRegistration);
+		}
+
+	}
+
+	@Configuration
+	@EnableWebFluxSecurity
+	@Import(ProviderIssuerMissingRegistrationConfig.class)
+	static class ProviderIssuerMissingConfig {
+
+		@Bean
+		@Order(1)
+		SecurityWebFilterChain filters(ServerHttpSecurity http) throws Exception {
+			// @formatter:off
+			http
+					.authorizeExchange((authorize) -> authorize.anyExchange().authenticated())
+					.oauth2Login(Customizer.withDefaults())
+					.oidcLogout((oidc) -> oidc.backChannel(Customizer.withDefaults()));
+			// @formatter:on
+
+			return http.build();
+		}
+
+	}
+
 	@Configuration
 	@EnableWebFluxSecurity
 	@EnableWebFlux
@@ -537,6 +609,9 @@ public class OidcLogoutSpecTests {
 		@Autowired
 		ClientRegistration registration;

+		@Autowired(required = false)
+		MockWebServer web;
+
 		static ServerWebExchangeMatcher or(String... patterns) {
 			List<ServerWebExchangeMatcher> matchers = new ArrayList<>();
 			for (String pattern : patterns) {
@@ -581,7 +656,7 @@ public class OidcLogoutSpecTests {
 		Map<String, Object> accessToken(WebSession session) {
 			JwtEncoderParameters parameters = JwtEncoderParameters
 					.from(JwtClaimsSet.builder().id("id").subject(this.username)
-							.issuer(this.registration.getProviderDetails().getIssuerUri()).issuedAt(Instant.now())
+							.issuer(getIssuerUri()).issuedAt(Instant.now())
 							.expiresAt(Instant.now().plusSeconds(86400)).claim("scope", "openid").build());
 			String token = this.encoder.encode(parameters).getTokenValue();
 			return new OIDCTokens(idToken(session.getId()), new BearerAccessToken(token, 86400, new Scope("openid")), null)
@@ -589,7 +664,7 @@ public class OidcLogoutSpecTests {
 		}

 		String idToken(String sessionId) {
-			OidcIdToken token = TestOidcIdTokens.idToken().issuer(this.registration.getProviderDetails().getIssuerUri())
+			OidcIdToken token = TestOidcIdTokens.idToken().issuer(getIssuerUri())
 					.subject(this.username).expiresAt(Instant.now().plusSeconds(86400))
 					.audience(List.of(this.registration.getClientId())).nonce(this.nonce)
 					.claim(LogoutTokenClaimNames.SID, sessionId).build();
@@ -598,6 +673,13 @@ public class OidcLogoutSpecTests {
 			return this.encoder.encode(parameters).getTokenValue();
 		}

+		private String getIssuerUri() {
+			if (this.web == null) {
+				return TestClientRegistrations.clientRegistration().build().getProviderDetails().getIssuerUri();
+			}
+			return this.web.url("/").toString();
+		}
+
 		@GetMapping("/user")
 		Map<String, Object> userinfo() {
 			return Map.of("sub", this.username, "id", this.username);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@

 package org.springframework.security.authentication;

+import java.util.Locale;
+
 import io.micrometer.common.KeyValues;
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationConvention;
@@ -53,7 +55,7 @@ public final class AuthenticationObservationConvention
 			if (authenticationType.endsWith("Authentication")) {
 				authenticationType = authenticationType.substring(0, authenticationType.lastIndexOf("Authentication"));
 			}
-			return "authenticate " + authenticationType.toLowerCase();
+			return "authenticate " + authenticationType.toLowerCase(Locale.ENGLISH);
 		}
 		return "authenticate";
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -79,10 +79,10 @@ public class SimpleAttributes2GrantedAuthoritiesMapper
 	 */
 	private GrantedAuthority getGrantedAuthority(String attribute) {
 		if (isConvertAttributeToLowerCase()) {
-			attribute = attribute.toLowerCase(Locale.getDefault());
+			attribute = attribute.toLowerCase(Locale.ROOT);
 		}
 		else if (isConvertAttributeToUpperCase()) {
-			attribute = attribute.toUpperCase(Locale.getDefault());
+			attribute = attribute.toUpperCase(Locale.ROOT);
 		}
 		if (isAddPrefixIfAlreadyExisting() || !attribute.startsWith(getAttributePrefix())) {
 			return new SimpleGrantedAuthority(getAttributePrefix() + attribute);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.core.authority.mapping;

 import java.util.Collection;
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Set;

 import org.springframework.beans.factory.InitializingBean;
@@ -71,10 +72,10 @@ public final class SimpleAuthorityMapper implements GrantedAuthoritiesMapper, In

 	private GrantedAuthority mapAuthority(String name) {
 		if (this.convertToUpperCase) {
-			name = name.toUpperCase();
+			name = name.toUpperCase(Locale.ROOT);
 		}
 		else if (this.convertToLowerCase) {
-			name = name.toLowerCase();
+			name = name.toLowerCase(Locale.ROOT);
 		}
 		if (this.prefix.length() > 0 && !name.startsWith(this.prefix)) {
 			name = this.prefix + name;
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.core.userdetails;

 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;

@@ -91,7 +92,7 @@ public class MapReactiveUserDetailsService implements ReactiveUserDetailsService
 	}

 	private String getKey(String username) {
-		return username.toLowerCase();
+		return username.toLowerCase(Locale.ROOT);
 	}

 }
@@ -19,6 +19,7 @@ package org.springframework.security.core.userdetails.memory;
 import java.beans.PropertyEditorSupport;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;

 import org.springframework.util.StringUtils;

@@ -45,10 +46,10 @@ public class UserAttributeEditor extends PropertyEditorSupport {
 				userAttrib.setPassword(currentToken);
 			}
 			else {
-				if (currentToken.toLowerCase().equals("enabled")) {
+				if (currentToken.toLowerCase(Locale.ENGLISH).equals("enabled")) {
 					userAttrib.setEnabled(true);
 				}
-				else if (currentToken.toLowerCase().equals("disabled")) {
+				else if (currentToken.toLowerCase(Locale.ENGLISH).equals("disabled")) {
 					userAttrib.setEnabled(false);
 				}
 				else {
@@ -75,7 +75,6 @@ public final class SecurityJackson2Modules {

 	private static final List<String> securityJackson2ModuleClasses = Arrays.asList(
 			"org.springframework.security.jackson2.CoreJackson2Module",
-			"org.springframework.security.cas.jackson2.CasJackson2Module",
 			"org.springframework.security.web.jackson2.WebJackson2Module",
 			"org.springframework.security.web.server.jackson2.WebServerJackson2Module");

@@ -89,6 +88,8 @@ public final class SecurityJackson2Modules {

 	private static final String saml2Jackson2ModuleClass = "org.springframework.security.saml2.jackson2.Saml2Jackson2Module";

+	private static final String casJackson2ModuleClass = "org.springframework.security.cas.jackson2.CasJackson2Module";
+
 	private static final boolean webServletPresent;

 	private static final boolean oauth2ClientPresent;
@@ -99,6 +100,8 @@ public final class SecurityJackson2Modules {

 	private static final boolean saml2JacksonPresent;

+	private static final boolean casJacksonPresent;
+
 	static {
 		ClassLoader classLoader = SecurityJackson2Modules.class.getClassLoader();
 		webServletPresent = ClassUtils.isPresent("jakarta.servlet.http.Cookie", classLoader);
@@ -107,6 +110,7 @@ public final class SecurityJackson2Modules {
 		javaTimeJacksonPresent = ClassUtils.isPresent(javaTimeJackson2ModuleClass, classLoader);
 		ldapJacksonPresent = ClassUtils.isPresent(ldapJackson2ModuleClass, classLoader);
 		saml2JacksonPresent = ClassUtils.isPresent(saml2Jackson2ModuleClass, classLoader);
+		casJacksonPresent = ClassUtils.isPresent(casJackson2ModuleClass, classLoader);
 	}

 	private SecurityJackson2Modules() {
@@ -160,6 +164,9 @@ public final class SecurityJackson2Modules {
 		if (saml2JacksonPresent) {
 			addToModulesList(loader, modules, saml2Jackson2ModuleClass);
 		}
+		if (casJacksonPresent) {
+			addToModulesList(loader, modules, casJackson2ModuleClass);
+		}
 		return modules;
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.security.provisioning;
 import java.util.Collection;
 import java.util.Enumeration;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Properties;

@@ -96,23 +97,23 @@ public class InMemoryUserDetailsManager implements UserDetailsManager, UserDetai
 	@Override
 	public void createUser(UserDetails user) {
 		Assert.isTrue(!userExists(user.getUsername()), "user should not exist");
-		this.users.put(user.getUsername().toLowerCase(), new MutableUser(user));
+		this.users.put(user.getUsername().toLowerCase(Locale.ROOT), new MutableUser(user));
 	}

 	@Override
 	public void deleteUser(String username) {
-		this.users.remove(username.toLowerCase());
+		this.users.remove(username.toLowerCase(Locale.ROOT));
 	}

 	@Override
 	public void updateUser(UserDetails user) {
 		Assert.isTrue(userExists(user.getUsername()), "user should exist");
-		this.users.put(user.getUsername().toLowerCase(), new MutableUser(user));
+		this.users.put(user.getUsername().toLowerCase(Locale.ROOT), new MutableUser(user));
 	}

 	@Override
 	public boolean userExists(String username) {
-		return this.users.containsKey(username.toLowerCase());
+		return this.users.containsKey(username.toLowerCase(Locale.ROOT));
 	}

 	@Override
@@ -143,14 +144,14 @@ public class InMemoryUserDetailsManager implements UserDetailsManager, UserDetai
 	@Override
 	public UserDetails updatePassword(UserDetails user, String newPassword) {
 		String username = user.getUsername();
-		MutableUserDetails mutableUser = this.users.get(username.toLowerCase());
+		MutableUserDetails mutableUser = this.users.get(username.toLowerCase(Locale.ROOT));
 		mutableUser.setPassword(newPassword);
 		return mutableUser;
 	}

 	@Override
 	public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
-		UserDetails user = this.users.get(username.toLowerCase());
+		UserDetails user = this.users.get(username.toLowerCase(Locale.ROOT));
 		if (user == null) {
 			throw new UsernameNotFoundException(username);
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.crypto.password;

 import java.security.MessageDigest;
 import java.util.Base64;
+import java.util.Locale;

 import org.springframework.security.crypto.codec.Utf8;
 import org.springframework.security.crypto.keygen.BytesKeyGenerator;
@@ -50,11 +51,11 @@ public class LdapShaPasswordEncoder implements PasswordEncoder {

 	private static final String SSHA_PREFIX = "{SSHA}";

-	private static final String SSHA_PREFIX_LC = SSHA_PREFIX.toLowerCase();
+	private static final String SSHA_PREFIX_LC = SSHA_PREFIX.toLowerCase(Locale.ENGLISH);

 	private static final String SHA_PREFIX = "{SHA}";

-	private static final String SHA_PREFIX_LC = SHA_PREFIX.toLowerCase();
+	private static final String SHA_PREFIX_LC = SHA_PREFIX.toLowerCase(Locale.ENGLISH);

 	private BytesKeyGenerator saltGenerator;

@@ -30,7 +30,7 @@ urls:
  redirect_facility: httpd
 ui:
  bundle:
-    url: https://github.com/spring-io/antora-ui-spring/releases/download/v0.4.16/ui-bundle.zip
+    url: https://github.com/spring-io/antora-ui-spring/releases/download/v0.4.17/ui-bundle.zip
    snapshot: true
 runtime:
  log:
@@ -153,6 +153,7 @@
 *** xref:reactive/exploits/csrf.adoc[CSRF]
 *** xref:reactive/exploits/headers.adoc[Headers]
 *** xref:reactive/exploits/http.adoc[HTTP Requests]
+*** xref:reactive/exploits/firewall.adoc[]
 ** Integrations
 *** xref:reactive/integrations/cors.adoc[CORS]
 *** xref:reactive/integrations/rsocket.adoc[RSocket]
@@ -0,0 +1,234 @@
+[[webflux-serverwebexchangefirewall]]
+= ServerWebExchangeFirewall
+
+There are various ways a request can be created by malicious users that can exploit applications.
+Spring Security provides the `ServerWebExchangeFirewall` to allow rejecting requests that look malicious.
+The default implementation is `StrictServerWebExchangeFirewall` which rejects malicious requests.
+
+For example a request could contain path-traversal sequences (such as `/../`) or multiple forward slashes (`//`) that could also cause pattern-matches to fail.
+Some containers normalize these out before performing the servlet mapping, but others do not.
+To protect against issues like these, `WebFilterChainProxy` uses a `ServerWebExchangeFirewall` strategy to check and wrap the request.
+By default, un-normalized requests are automatically rejected, and path parameters are removed for matching purposes.
+(So, for example, an original request path of `/secure;hack=1/somefile.html;hack=2` is returned as `/secure/somefile.html`.)
+It is, therefore, essential that a `WebFilterChainProxy` is used.
+
+In practice, we recommend that you use method security at your service layer, to control access to your application, rather than rely entirely on the use of security constraints defined at the web-application level.
+URLs change, and it is difficult to take into account all the possible URLs that an application might support and how requests might be manipulated.
+You should restrict yourself to using a few simple patterns that are simple to understand.
+Always try to use a "`deny-by-default`" approach, where you have a catch-all wildcard (`/**` or `**`) defined last to deny access.
+
+Security defined at the service layer is much more robust and harder to bypass, so you should always take advantage of Spring Security's method security options.
+
+You can customize the `ServerWebExchangeFirewall` by exposing it as a Bean.
+
+.Allow Matrix Variables
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+@Bean
+public StrictServerWebExchangeFirewall httpFirewall() {
+    StrictServerWebExchangeFirewall firewall = new StrictServerWebExchangeFirewall();
+    firewall.setAllowSemicolon(true);
+    return firewall;
+}
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+@Bean
+fun httpFirewall(): StrictServerWebExchangeFirewall {
+    val firewall = StrictServerWebExchangeFirewall()
+    firewall.setAllowSemicolon(true)
+    return firewall
+}
+----
+======
+
+To protect against https://www.owasp.org/index.php/Cross_Site_Tracing[Cross Site Tracing (XST)] and https://www.owasp.org/index.php/Test_HTTP_Methods_(OTG-CONFIG-006)[HTTP Verb Tampering], the `StrictServerWebExchangeFirewall` provides an allowed list of valid HTTP methods that are allowed.
+The default valid methods are `DELETE`, `GET`, `HEAD`, `OPTIONS`, `PATCH`, `POST`, and `PUT`.
+If your application needs to modify the valid methods, you can configure a custom `StrictServerWebExchangeFirewall` bean.
+The following example allows only HTTP `GET` and `POST` methods:
+
+
+.Allow Only GET & POST
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+@Bean
+public StrictServerWebExchangeFirewall httpFirewall() {
+    StrictServerWebExchangeFirewall firewall = new StrictServerWebExchangeFirewall();
+    firewall.setAllowedHttpMethods(Arrays.asList("GET", "POST"));
+    return firewall;
+}
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+@Bean
+fun httpFirewall(): StrictServerWebExchangeFirewall {
+    val firewall = StrictServerWebExchangeFirewall()
+    firewall.setAllowedHttpMethods(listOf("GET", "POST"))
+    return firewall
+}
+----
+======
+
+If you must allow any HTTP method (not recommended), you can use `StrictServerWebExchangeFirewall.setUnsafeAllowAnyHttpMethod(true)`.
+Doing so entirely disables validation of the HTTP method.
+
+
+[[webflux-serverwebexchangefirewall-headers-parameters]]
+`StrictServerWebExchangeFirewall` also checks header names and values and parameter names.
+It requires that each character have a defined code point and not be a control character.
+
+This requirement can be relaxed or adjusted as necessary by using the following methods:
+
+* `StrictServerWebExchangeFirewall#setAllowedHeaderNames(Predicate)`
+* `StrictServerWebExchangeFirewall#setAllowedHeaderValues(Predicate)`
+* `StrictServerWebExchangeFirewall#setAllowedParameterNames(Predicate)`
+
+[NOTE]
+====
+Parameter values can be also controlled with `setAllowedParameterValues(Predicate)`.
+====
+
+For example, to switch off this check, you can wire your `StrictServerWebExchangeFirewall` with `Predicate` instances that always return `true`:
+
+.Allow Any Header Name, Header Value, and Parameter Name
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+@Bean
+public StrictServerWebExchangeFirewall httpFirewall() {
+    StrictServerWebExchangeFirewall firewall = new StrictServerWebExchangeFirewall();
+    firewall.setAllowedHeaderNames((header) -> true);
+    firewall.setAllowedHeaderValues((header) -> true);
+    firewall.setAllowedParameterNames((parameter) -> true);
+    return firewall;
+}
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+@Bean
+fun httpFirewall(): StrictServerWebExchangeFirewall {
+    val firewall = StrictServerWebExchangeFirewall()
+    firewall.setAllowedHeaderNames { true }
+    firewall.setAllowedHeaderValues { true }
+    firewall.setAllowedParameterNames { true }
+    return firewall
+}
+----
+======
+
+Alternatively, there might be a specific value that you need to allow.
+
+For example, iPhone Xʀ uses a `User-Agent` that includes a character that is not in the ISO-8859-1 charset.
+Due to this fact, some application servers parse this value into two separate characters, the latter being an undefined character.
+
+You can address this with the `setAllowedHeaderValues` method:
+
+.Allow Certain User Agents
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+@Bean
+public StrictServerWebExchangeFirewall httpFirewall() {
+    StrictServerWebExchangeFirewall firewall = new StrictServerWebExchangeFirewall();
+    Pattern allowed = Pattern.compile("[\\p{IsAssigned}&&[^\\p{IsControl}]]*");
+    Pattern userAgent = ...;
+    firewall.setAllowedHeaderValues((header) -> allowed.matcher(header).matches() || userAgent.matcher(header).matches());
+    return firewall;
+}
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+@Bean
+fun httpFirewall(): StrictServerWebExchangeFirewall {
+    val firewall = StrictServerWebExchangeFirewall()
+    val allowed = Pattern.compile("[\\p{IsAssigned}&&[^\\p{IsControl}]]*")
+    val userAgent = Pattern.compile(...)
+    firewall.setAllowedHeaderValues { allowed.matcher(it).matches() || userAgent.matcher(it).matches() }
+    return firewall
+}
+----
+======
+
+In the case of header values, you may instead consider parsing them as UTF-8 at verification time:
+
+.Parse Headers As UTF-8
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+firewall.setAllowedHeaderValues((header) -> {
+    String parsed = new String(header.getBytes(ISO_8859_1), UTF_8);
+    return allowed.matcher(parsed).matches();
+});
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+firewall.setAllowedHeaderValues {
+    val parsed = String(header.getBytes(ISO_8859_1), UTF_8)
+    return allowed.matcher(parsed).matches()
+}
+----
+======
+
+The `ServerExchangeRejectedHandler` interface is used to handle `ServerExchangeRejectedException` throw by Spring Security's `ServerWebExchangeFirewall`.
+By default `HttpStatusExchangeRejectedHandler` is used to send an HTTP 400 response to clients when a request is rejected.
+To customize the behavior, users can expose a `ServerExchangeRejectedHandler` Bean.
+For example, the following will send an HTTP 404 when the request is rejected:
+
+
+.Send 404 on Request Rejected
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+@Bean
+ServerExchangeRejectedHandler rejectedHandler() {
+	return new HttpStatusExchangeRejectedHandler(HttpStatus.NOT_FOUND);
+}
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+@Bean
+fun rejectedHandler(): ServerExchangeRejectedHandler {
+    return HttpStatusExchangeRejectedHandler(HttpStatus.NOT_FOUND)
+}
+----
+======
+
+Handling can be completely customized by creating a custom `ServerExchangeRejectedHandler` implementation.
@@ -17,7 +17,7 @@ Java::
 [source,java,role="primary"]
 ----
@Bean
-CorsConfigurationSource corsConfigurationSource() {
+UrlBasedCorsConfigurationSource corsConfigurationSource() {
 	CorsConfiguration configuration = new CorsConfiguration();
 	configuration.setAllowedOrigins(Arrays.asList("https://example.com"));
 	configuration.setAllowedMethods(Arrays.asList("GET","POST"));
@@ -32,7 +32,7 @@ Kotlin::
 [source,kotlin,role="secondary"]
 ----
@Bean
-fun corsConfigurationSource(): CorsConfigurationSource {
+fun corsConfigurationSource(): UrlBasedCorsConfigurationSource {
    val configuration = CorsConfiguration()
    configuration.allowedOrigins = listOf("https://example.com")
    configuration.allowedMethods = listOf("GET", "POST")
@@ -135,7 +135,7 @@ To enable this, you can stand up the Back-Channel Logout endpoint in the DSL lik
 ======
 Java::
 +
-[source=java,role="primary"]
+[source,java,role="primary"]
 ----
@Bean
 public SecurityWebFilterChain filterChain(ServerHttpSecurity http) throws Exception {
@@ -153,7 +153,7 @@ public SecurityWebFilterChain filterChain(ServerHttpSecurity http) throws Except

 Kotlin::
 +
-[source=kotlin,role="secondary"]
+[source,kotlin,role="secondary"]
 ----
@Bean
 open fun filterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
@@ -187,7 +187,7 @@ Consider a `ClientRegistration` whose identifier is `registrationId`.

 The overall flow for a Back-Channel logout is like this:

-1. At login time, Spring Security correlates the ID Token, CSRF Token, and Provider Session ID (if any) to your application's session id in its `ReactiveOidcSessionStrategy` implementation.
+1. At login time, Spring Security correlates the ID Token, CSRF Token, and Provider Session ID (if any) to your application's session id in its `ReactiveOidcSessionRegistry` implementation.
 2. Then at logout time, your OIDC Provider makes an API call to `/logout/connect/back-channel/registrationId` including a Logout Token that indicates either the `sub` (the End User) or the `sid` (the Provider Session ID) to logout.
 3. Spring Security validates the token's signature and claims.
 4. If the token contains a `sid` claim, then only the Client's session that correlates to that provider session is terminated.
@@ -197,38 +197,38 @@ The overall flow for a Back-Channel logout is like this:
 Remember that Spring Security's OIDC support is multi-tenant.
 This means that it will only terminate sessions whose Client matches the `aud` claim in the Logout Token.

-=== Customizing the OIDC Provider Session Strategy
+=== Customizing the OIDC Provider Session Registry

 By default, Spring Security stores in-memory all links between the OIDC Provider session and the Client session.

 There are a number of circumstances, like a clustered application, where it would be nice to store this instead in a separate location, like a database.

-You can achieve this by configuring a custom `ReactiveOidcSessionStrategy`, like so:
+You can achieve this by configuring a custom `ReactiveOidcSessionRegistry`, like so:

 [tabs]
 ======
 Java::
 +
-[source=java,role="primary"]
+[source,java,role="primary"]
 ----
@Component
-public final class MySpringDataOidcSessionStrategy implements OidcSessionStrategy {
+public final class MySpringDataOidcSessionRegistry implements ReactiveOidcSessionRegistry {
    private final OidcProviderSessionRepository sessions;

    // ...

    @Override
-    public void saveSessionInformation(OidcSessionInformation info) {
-        this.sessions.save(info);
+    public Mono<void> saveSessionInformation(OidcSessionInformation info) {
+        return this.sessions.save(info);
    }

    @Override
-    public OidcSessionInformation(String clientSessionId) {
+    public Mono<OidcSessionInformation> removeSessionInformation(String clientSessionId) {
       return this.sessions.removeByClientSessionId(clientSessionId);
    }

    @Override
-    public Iterable<OidcSessionInformation> removeSessionInformation(OidcLogoutToken token) {
+    public Flux<OidcSessionInformation> removeSessionInformation(OidcLogoutToken token) {
        return token.getSessionId() != null ?
            this.sessions.removeBySessionIdAndIssuerAndAudience(...) :
            this.sessions.removeBySubjectAndIssuerAndAudience(...);
@@ -238,10 +238,10 @@ public final class MySpringDataOidcSessionStrategy implements OidcSessionStrateg

 Kotlin::
 +
-[source=kotlin,role="secondary"]
+[source,kotlin,role="secondary"]
 ----
@Component
-class MySpringDataOidcSessionStrategy: ReactiveOidcSessionStrategy {
+class MySpringDataOidcSessionRegistry: ReactiveOidcSessionRegistry {
    val sessions: OidcProviderSessionRepository

    // ...
@@ -326,156 +326,7 @@ Normally, Spring Security builds an `AuthenticationManager` internally composed
 In certain cases, it may still be desired to customize the instance of `AuthenticationManager` used by Spring Security.
 For example, you may need to simply disable xref:servlet/authentication/architecture.adoc#servlet-authentication-providermanager-erasing-credentials[credential erasure] for cached users.

-The recommended way to do this is to simply publish your own `AuthenticationManager` bean, and Spring Security will use it.
-You can publish an `AuthenticationManager` using the following configuration:
-
-.Publish `AuthenticationManager` bean for Spring Security
-[tabs]
-=====
-Java::
-+
-[source,java,role="primary"]
----
-@Configuration
-@EnableWebSecurity
-public class SecurityConfig {
-
-	@Bean
-	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
-		http
-			.authorizeHttpRequests((authorize) -> authorize
-				.requestMatchers("/login").permitAll()
-				.anyRequest().authenticated()
-			)
-			.httpBasic(Customizer.withDefaults())
-			.formLogin(Customizer.withDefaults());
-
-		return http.build();
-	}
-
-	@Bean
-	public AuthenticationManager authenticationManager(
-			UserDetailsService userDetailsService,
-			PasswordEncoder passwordEncoder) {
-		DaoAuthenticationProvider authenticationProvider = new DaoAuthenticationProvider();
-		authenticationProvider.setUserDetailsService(userDetailsService);
-		authenticationProvider.setPasswordEncoder(passwordEncoder);
-
-		ProviderManager providerManager = new ProviderManager(authenticationProvider);
-		providerManager.setEraseCredentialsAfterAuthentication(false);
-
-		return providerManager;
-	}
-
-	@Bean
-	public UserDetailsService userDetailsService() {
-		UserDetails userDetails = User.withDefaultPasswordEncoder()
-			.username("user")
-			.password("password")
-			.roles("USER")
-			.build();
-
-		return new InMemoryUserDetailsManager(userDetails);
-	}
-
-	@Bean
-	public PasswordEncoder passwordEncoder() {
-		return PasswordEncoderFactories.createDelegatingPasswordEncoder();
-	}
-
-}
----
-
-XML::
-+
-[source,xml,role="secondary"]
----
-<http>
-	<intercept-url pattern="/login" access="permitAll"/>
-	<intercept-url pattern="/**" access="authenticated"/>
-	<form-login />
-	<http-basic />
-
-	<bean id="authenticationManager"
-			class="org.springframework.security.authentication.ProviderManager">
-		<constructor-arg>
-			<bean class="org.springframework.security.authentication.dao.DaoAuthenticationProvider">
-				<property name="userDetailsService" ref="userDetailsService" />
-				<property name="passwordEncoder" ref="passwordEncoder" />
-			</bean>
-		</constructor-arg>
-	</bean>
-
-	<user-service id="userDetailsService">
-		<user name="user"
-			password="{noop}password"
-			authorities="ROLE_USER" />
-	</user-service>
-
-	<bean id="passwordEncoder"
-			class="org.springframework.security.crypto.factory.PasswordEncoderFactories" factory-method="createDelegatingPasswordEncoder"/>
-</http>
----
-
-Kotlin::
-+
-[source,kotlin,role="secondary"]
----
-import org.springframework.security.config.annotation.web.invoke
-
-@Configuration
-@EnableWebSecurity
-class SecurityConfig {
-
-	@Bean
-	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
-		http {
-			authorizeHttpRequests {
-				authorize("/login", permitAll)
-				authorize(anyRequest, authenticated)
-			}
-			formLogin { }
-			httpBasic { }
-		}
-
-		return http.build()
-	}
-
-	@Bean
-	fun authenticationManager(
-			userDetailsService: UserDetailsService,
-			passwordEncoder: PasswordEncoder): AuthenticationManager {
-		val authenticationProvider = DaoAuthenticationProvider()
-		authenticationProvider.setUserDetailsService(userDetailsService)
-		authenticationProvider.setPasswordEncoder(passwordEncoder)
-
-		val providerManager = ProviderManager(authenticationProvider)
-		providerManager.eraseCredentialsAfterAuthentication = false
-
-		return providerManager
-	}
-
-	@Bean
-	fun userDetailsService(): UserDetailsService {
-		val user = User.withDefaultPasswordEncoder()
-			.username("user")
-			.password("password")
-			.roles("USER")
-			.build()
-
-		return InMemoryUserDetailsManager(user)
-	}
-
-	@Bean
-	fun passwordEncoder(): PasswordEncoder {
-		return PasswordEncoderFactories.createDelegatingPasswordEncoder()
-	}
-
-}
----
-=====
-
-Alternatively, you can take advantage of the fact that the `AuthenticationManagerBuilder` used to build Spring Security's global `AuthenticationManager` is published as a bean.
+To do this, you can take advantage of the fact that the `AuthenticationManagerBuilder` used to build Spring Security's global `AuthenticationManager` is published as a bean.
 You can configure the builder as follows:

 .Configure global `AuthenticationManagerBuilder`
@@ -539,3 +390,142 @@ class SecurityConfig {
 }
 ----
 =====
+
+Alternatively, you may configure a local `AuthenticationManager` to override the global one.
+
+.Configure local `AuthenticationManager` for Spring Security
+[tabs]
+=====
+Java::
+
+[source,java,role="primary"]
+----
+@Configuration
+@EnableWebSecurity
+public class SecurityConfig {
+
+	@Bean
+	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
+		http
+			.authorizeHttpRequests((authorize) -> authorize
+				.anyRequest().authenticated()
+			)
+			.httpBasic(Customizer.withDefaults())
+			.formLogin(Customizer.withDefaults())
+			.authenticationManager(authenticationManager());
+
+		return http.build();
+	}
+
+	private AuthenticationManager authenticationManager() {
+		DaoAuthenticationProvider authenticationProvider = new DaoAuthenticationProvider();
+		authenticationProvider.setUserDetailsService(userDetailsService());
+		authenticationProvider.setPasswordEncoder(passwordEncoder());
+
+		ProviderManager providerManager = new ProviderManager(authenticationProvider);
+		providerManager.setEraseCredentialsAfterAuthentication(false);
+
+		return providerManager;
+	}
+
+	private UserDetailsService userDetailsService() {
+		UserDetails userDetails = User.withDefaultPasswordEncoder()
+			.username("user")
+			.password("password")
+			.roles("USER")
+			.build();
+
+		return new InMemoryUserDetailsManager(userDetails);
+	}
+
+	private PasswordEncoder passwordEncoder() {
+		return PasswordEncoderFactories.createDelegatingPasswordEncoder();
+	}
+
+}
+----
+
+XML::
+
+[source,xml,role="secondary"]
+----
+<http authentication-manager-ref="authenticationManager">
+	<intercept-url pattern="/**" access="authenticated"/>
+	<form-login />
+	<http-basic />
+
+	<bean id="authenticationManager"
+			class="org.springframework.security.authentication.ProviderManager">
+		<constructor-arg>
+			<bean class="org.springframework.security.authentication.dao.DaoAuthenticationProvider">
+				<property name="userDetailsService" ref="userDetailsService" />
+				<property name="passwordEncoder" ref="passwordEncoder" />
+			</bean>
+		</constructor-arg>
+	</bean>
+
+	<user-service id="userDetailsService">
+		<user name="user"
+			password="{noop}password"
+			authorities="ROLE_USER" />
+	</user-service>
+
+	<bean id="passwordEncoder"
+			class="org.springframework.security.crypto.factory.PasswordEncoderFactories" factory-method="createDelegatingPasswordEncoder"/>
+</http>
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+import org.springframework.security.config.annotation.web.invoke
+
+@Configuration
+@EnableWebSecurity
+class SecurityConfig {
+
+	@Bean
+	fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
+		http {
+			authorizeHttpRequests {
+				authorize(anyRequest, authenticated)
+			}
+			formLogin { }
+			httpBasic { }
+			authenticationManager = authenticationManager()
+		}
+
+		return http.build()
+	}
+
+	@Bean
+	fun authenticationManager(): AuthenticationManager {
+		val authenticationProvider = DaoAuthenticationProvider()
+		authenticationProvider.setUserDetailsService(userDetailsService())
+		authenticationProvider.setPasswordEncoder(passwordEncoder())
+
+		val providerManager = ProviderManager(authenticationProvider)
+		providerManager.eraseCredentialsAfterAuthentication = false
+
+		return providerManager
+	}
+
+	private fun userDetailsService(): UserDetailsService {
+		val user = User.withDefaultPasswordEncoder()
+			.username("user")
+			.password("password")
+			.roles("USER")
+			.build()
+
+		return InMemoryUserDetailsManager(user)
+	}
+
+	private fun passwordEncoder(): PasswordEncoder {
+		return PasswordEncoderFactories.createDelegatingPasswordEncoder()
+	}
+
+}
+----
+=====
+
@@ -101,7 +101,7 @@ The `AuthorizationManager` interface contains two methods:
 ----
 AuthorizationDecision check(Supplier<Authentication> authentication, Object secureObject);

-default AuthorizationDecision verify(Supplier<Authentication> authentication, Object secureObject)
+default void verify(Supplier<Authentication> authentication, Object secureObject)
        throws AccessDeniedException {
    // ...
 }
@@ -16,7 +16,7 @@ Java::
 [source,java,role="primary"]
 ----
@Bean
-CorsConfigurationSource corsConfigurationSource() {
+UrlBasedCorsConfigurationSource corsConfigurationSource() {
    CorsConfiguration configuration = new CorsConfiguration();
    configuration.setAllowedOrigins(Arrays.asList("https://example.com"));
    configuration.setAllowedMethods(Arrays.asList("GET","POST"));
@@ -31,7 +31,7 @@ Kotlin::
 [source,kotlin,role="secondary"]
 ----
@Bean
-fun corsConfigurationSource(): CorsConfigurationSource {
+fun corsConfigurationSource(): UrlBasedCorsConfigurationSource {
    val configuration = CorsConfiguration()
    configuration.allowedOrigins = listOf("https://example.com")
    configuration.allowedMethods = listOf("GET", "POST")
@@ -147,7 +147,7 @@ public class WebSecurityConfig {
 		return http.build();
 	}

-	CorsConfigurationSource apiConfigurationSource() {
+	UrlBasedCorsConfigurationSource apiConfigurationSource() {
 		CorsConfiguration configuration = new CorsConfiguration();
 		configuration.setAllowedOrigins(Arrays.asList("https://api.example.com"));
 		configuration.setAllowedMethods(Arrays.asList("GET","POST"));
@@ -156,7 +156,7 @@ public class WebSecurityConfig {
 		return source;
 	}

-	CorsConfigurationSource myWebsiteConfigurationSource() {
+	UrlBasedCorsConfigurationSource myWebsiteConfigurationSource() {
 		CorsConfiguration configuration = new CorsConfiguration();
 		configuration.setAllowedOrigins(Arrays.asList("https://example.com"));
 		configuration.setAllowedMethods(Arrays.asList("GET","POST"));
@@ -173,7 +173,7 @@ Kotlin::
 [source,kotlin,role="secondary"]
 ----
@Bean
-fun corsConfigurationSource(): CorsConfigurationSource {
+fun corsConfigurationSource(): UrlBasedCorsConfigurationSource {
    val configuration = CorsConfiguration()
    configuration.allowedOrigins = listOf("https://example.com")
    configuration.allowedMethods = listOf("GET", "POST")
@@ -134,7 +134,7 @@ To enable this, you can stand up the Back-Channel Logout endpoint in the DSL lik
 ======
 Java::
 +
-[source=java,role="primary"]
+[source,java,role="primary"]
 ----
@Bean
 public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
@@ -152,7 +152,7 @@ public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {

 Kotlin::
 +
-[source=kotlin,role="secondary"]
+[source,kotlin,role="secondary"]
 ----
@Bean
 open fun filterChain(http: HttpSecurity): SecurityFilterChain {
@@ -176,7 +176,7 @@ Then, you need a way listen to events published by Spring Security to remove old
 ======
 Java::
 +
-[source=java,role="primary"]
+[source,java,role="primary"]
 ----
@Bean
 public HttpSessionEventPublisher sessionEventPublisher() {
@@ -186,7 +186,7 @@ public HttpSessionEventPublisher sessionEventPublisher() {

 Kotlin::
 +
-[source=kotlin,role="secondary"]
+[source,kotlin,role="secondary"]
 ----
@Bean
 open fun sessionEventPublisher(): HttpSessionEventPublisher {
@@ -213,7 +213,7 @@ Consider a `ClientRegistration` whose identifier is `registrationId`.

 The overall flow for a Back-Channel logout is like this:

-1. At login time, Spring Security correlates the ID Token, CSRF Token, and Provider Session ID (if any) to your application's session id in its `OidcSessionStrategy` implementation.
+1. At login time, Spring Security correlates the ID Token, CSRF Token, and Provider Session ID (if any) to your application's session id in its `OidcSessionRegistry` implementation.
 2. Then at logout time, your OIDC Provider makes an API call to `/logout/connect/back-channel/registrationId` including a Logout Token that indicates either the `sub` (the End User) or the `sid` (the Provider Session ID) to logout.
 3. Spring Security validates the token's signature and claims.
 4. If the token contains a `sid` claim, then only the Client's session that correlates to that provider session is terminated.
@@ -223,22 +223,22 @@ The overall flow for a Back-Channel logout is like this:
 Remember that Spring Security's OIDC support is multi-tenant.
 This means that it will only terminate sessions whose Client matches the `aud` claim in the Logout Token.

-=== Customizing the OIDC Provider Session Strategy
+=== Customizing the OIDC Provider Session Registry

 By default, Spring Security stores in-memory all links between the OIDC Provider session and the Client session.

 There are a number of circumstances, like a clustered application, where it would be nice to store this instead in a separate location, like a database.

-You can achieve this by configuring a custom `OidcSessionStrategy`, like so:
+You can achieve this by configuring a custom `OidcSessionRegistry`, like so:

 [tabs]
 ======
 Java::
 +
-[source=java,role="primary"]
+[source,java,role="primary"]
 ----
@Component
-public final class MySpringDataOidcSessionStrategy implements OidcSessionStrategy {
+public final class MySpringDataOidcSessionRegistry implements OidcSessionRegistry {
    private final OidcProviderSessionRepository sessions;

    // ...
@@ -249,7 +249,7 @@ public final class MySpringDataOidcSessionStrategy implements OidcSessionStrateg
    }

    @Override
-    public OidcSessionInformation(String clientSessionId) {
+    public OidcSessionInformation removeSessionInformation(String clientSessionId) {
       return this.sessions.removeByClientSessionId(clientSessionId);
    }

@@ -264,10 +264,10 @@ public final class MySpringDataOidcSessionStrategy implements OidcSessionStrateg

 Kotlin::
 +
-[source=kotlin,role="secondary"]
+[source,kotlin,role="secondary"]
 ----
@Component
-class MySpringDataOidcSessionStrategy: OidcSessionStrategy {
+class MySpringDataOidcSessionRegistry: OidcSessionRegistry {
    val sessions: OidcProviderSessionRepository

    // ...
@@ -89,12 +89,12 @@ Next, let's see the architectural components that Spring Security uses to suppor
 {security-api-url}org/springframework/security/oauth2/server/resource/authentication/JwtAuthenticationProvider.html[`JwtAuthenticationProvider`] is an xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationprovider[`AuthenticationProvider`] implementation that leverages a <<oauth2resourceserver-jwt-decoder,`JwtDecoder`>> and <<oauth2resourceserver-jwt-authorization-extraction,`JwtAuthenticationConverter`>> to authenticate a JWT.

 Let's take a look at how `JwtAuthenticationProvider` works within Spring Security.
-The figure explains details of how the xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationmanager[`AuthenticationManager`] in figures from <<oauth2resourceserver-authentication-bearertokenauthenticationfilter,Reading the Bearer Token>> works.
+The figure explains details of how the xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationmanager[`AuthenticationManager`] in figures from xref:servlet/oauth2/resource-server/index.adoc#oauth2resourceserver-authentication-bearertokenauthenticationfilter[Reading the Bearer Token] works.

 .`JwtAuthenticationProvider` Usage
 image::{figures}/jwtauthenticationprovider.png[]

-image:{icondir}/number_1.png[] The authentication `Filter` from <<oauth2resourceserver-authentication-bearertokenauthenticationfilter,Reading the Bearer Token>> passes a `BearerTokenAuthenticationToken` to the `AuthenticationManager` which is implemented by xref:servlet/authentication/architecture.adoc#servlet-authentication-providermanager[`ProviderManager`].
+image:{icondir}/number_1.png[] The authentication `Filter` from xref:servlet/oauth2/resource-server/index.adoc#oauth2resourceserver-authentication-bearertokenauthenticationfilter[Reading the Bearer Token] passes a `BearerTokenAuthenticationToken` to the `AuthenticationManager` which is implemented by xref:servlet/authentication/architecture.adoc#servlet-authentication-providermanager[`ProviderManager`].

 image:{icondir}/number_2.png[] The `ProviderManager` is configured to use an xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationprovider[AuthenticationProvider] of type `JwtAuthenticationProvider`.

@@ -85,12 +85,12 @@ Next, let's see the architectural components that Spring Security uses to suppor
 {security-api-url}org/springframework/security/oauth2/server/resource/authentication/OpaqueTokenAuthenticationProvider.html[`OpaqueTokenAuthenticationProvider`] is an xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationprovider[`AuthenticationProvider`] implementation that leverages a <<oauth2resourceserver-opaque-introspector,`OpaqueTokenIntrospector`>> to authenticate an opaque token.

 Let's take a look at how `OpaqueTokenAuthenticationProvider` works within Spring Security.
-The figure explains details of how the xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationmanager[`AuthenticationManager`] in figures from <<oauth2resourceserver-authentication-bearertokenauthenticationfilter,Reading the Bearer Token>> works.
+The figure explains details of how the xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationmanager[`AuthenticationManager`] in figures from xref:servlet/oauth2/resource-server/index.adoc#oauth2resourceserver-authentication-bearertokenauthenticationfilter[Reading the Bearer Token] works.

 .`OpaqueTokenAuthenticationProvider` Usage
 image::{figures}/opaquetokenauthenticationprovider.png[]

-image:{icondir}/number_1.png[] The authentication `Filter` from <<oauth2resourceserver-authentication-bearertokenauthenticationfilter,Reading the Bearer Token>> passes a `BearerTokenAuthenticationToken` to the `AuthenticationManager` which is implemented by xref:servlet/authentication/architecture.adoc#servlet-authentication-providermanager[`ProviderManager`].
+image:{icondir}/number_1.png[] The authentication `Filter` from xref:servlet/oauth2/resource-server/index.adoc#oauth2resourceserver-authentication-bearertokenauthenticationfilter[Reading the Bearer Token] passes a `BearerTokenAuthenticationToken` to the `AuthenticationManager` which is implemented by xref:servlet/authentication/architecture.adoc#servlet-authentication-providermanager[`ProviderManager`].

 image:{icondir}/number_2.png[] The `ProviderManager` is configured to use an xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationprovider[AuthenticationProvider] of type `OpaqueTokenAuthenticationProvider`.

@@ -2,9 +2,9 @@
  "dependencies": {
    "antora": "3.2.0-alpha.6",
    "@antora/atlas-extension": "1.0.0-alpha.2",
-    "@antora/collector-extension": "1.0.0-beta.2",
+    "@antora/collector-extension": "1.0.0-beta.5",
    "@asciidoctor/tabs": "1.0.0-beta.6",
    "@springio/antora-extensions": "1.14.2",
-    "@springio/asciidoctor-extensions": "1.0.0-alpha.12"
+    "@springio/asciidoctor-extensions": "1.0.0-alpha.14"
  }
 }
@@ -40,4 +40,8 @@

 	<!-- Lambdas that we can't replace with a method reference because a closure is required -->
 	<suppress files="BearerTokenAuthenticationFilter\.java" checks="SpringLambda"/>
+
+	<!-- Ignore String.toUpperCase() and String.toLowerCase() checks in tests -->
+	<suppress files="[\\/]src[\\/]test[\\/]" checks="RegexpSinglelineJava" id="toLowerCaseWithoutLocale"/>
+	<suppress files="[\\/]src[\\/]test[\\/]" checks="RegexpSinglelineJava" id="toUpperCaseWithoutLocale"/>
 </suppressions>
@@ -30,5 +30,21 @@
 			<property name="message" value="Please use assertThatExceptionOfType." />
 			<property name="ignoreComments" value="true" />
 		</module>
+		<module name="com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineJavaCheck">
+			<property name="id" value="toLowerCaseWithoutLocale"/>
+			<property name="format" value="\.toLowerCase\(\)"/>
+			<property name="maximum" value="0"/>
+			<property name="message"
+					  value="String.toLowerCase() should be String.toLowerCase(Locale.ROOT) or String.toLowerCase(Locale.ENGLISH)"/>
+			<property name="ignoreComments" value="true"/>
+		</module>
+		<module name="com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineJavaCheck">
+			<property name="id" value="toUpperCaseWithoutLocale"/>
+			<property name="format" value="\.toUpperCase\(\)"/>
+			<property name="maximum" value="0"/>
+			<property name="message"
+					  value="String.toUpperCase() should be String.toUpperCase(Locale.ROOT) or String.toUpperCase(Locale.ENGLISH)"/>
+			<property name="ignoreComments" value="true"/>
+		</module>
 	</module>
 </module>
@@ -10,6 +10,7 @@ org.eclipse.jdt.core.codeComplete.staticFieldSuffixes=
 org.eclipse.jdt.core.codeComplete.staticFinalFieldPrefixes=
 org.eclipse.jdt.core.codeComplete.staticFinalFieldSuffixes=
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.methodParameters=generate
 org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.6
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
 org.eclipse.jdt.core.compiler.compliance=1.6
@@ -1,5 +1,5 @@
 springBootVersion=3.1.1
-version=6.2.6
+version=6.2.8
 samplesBranch=6.2.x
 org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.parallel=true
@@ -8,12 +8,12 @@ org-apache-directory-server = "1.5.5"
 org-apache-maven-resolver = "1.9.22"
 org-aspectj = "1.9.22.1"
 org-bouncycastle = "1.70"
-org-eclipse-jetty = "11.0.22"
+org-eclipse-jetty = "11.0.24"
 org-jetbrains-kotlin = "1.9.25"
 org-jetbrains-kotlinx = "1.7.3"
 org-mockito = "5.5.0"
 org-opensaml = "4.3.2"
-org-springframework = "6.1.12"
+org-springframework = "6.1.15"

 [libraries]
 ch-qos-logback-logback-classic = "ch.qos.logback:logback-classic:1.4.14"
@@ -26,9 +26,9 @@ com-squareup-okhttp3-mockwebserver = { module = "com.squareup.okhttp3:mockwebser
 com-squareup-okhttp3-okhttp = { module = "com.squareup.okhttp3:okhttp", version.ref = "com-squareup-okhttp3" }
 com-unboundid-unboundid-ldapsdk = "com.unboundid:unboundid-ldapsdk:6.0.11"
 commons-collections = "commons-collections:commons-collections:3.2.2"
-io-micrometer-micrometer-observation = "io.micrometer:micrometer-observation:1.12.9"
-io-mockk = "io.mockk:mockk:1.13.12"
-io-projectreactor-reactor-bom = "io.projectreactor:reactor-bom:2023.0.9"
+io-micrometer-micrometer-observation = "io.micrometer:micrometer-observation:1.12.13"
+io-mockk = "io.mockk:mockk:1.13.13"
+io-projectreactor-reactor-bom = "io.projectreactor:reactor-bom:2023.0.12"
 io-rsocket-rsocket-bom = { module = "io.rsocket:rsocket-bom", version.ref = "io-rsocket" }
 io-spring-javaformat-spring-javaformat-checkstyle = { module = "io.spring.javaformat:spring-javaformat-checkstyle", version.ref = "io-spring-javaformat" }
 io-spring-javaformat-spring-javaformat-gradle-plugin = { module = "io.spring.javaformat:spring-javaformat-gradle-plugin", version.ref = "io-spring-javaformat" }
@@ -40,7 +40,7 @@ jakarta-inject-jakarta-inject-api = "jakarta.inject:jakarta.inject-api:2.0.1"
 jakarta-persistence-jakarta-persistence-api = "jakarta.persistence:jakarta.persistence-api:3.1.0"
 jakarta-servlet-jakarta-servlet-api = "jakarta.servlet:jakarta.servlet-api:6.0.0"
 jakarta-servlet-jsp-jakarta-servlet-jsp-api = "jakarta.servlet.jsp:jakarta.servlet.jsp-api:3.1.1"
-jakarta-servlet-jsp-jstl-jakarta-servlet-jsp-jstl-api = "jakarta.servlet.jsp.jstl:jakarta.servlet.jsp.jstl-api:3.0.1"
+jakarta-servlet-jsp-jstl-jakarta-servlet-jsp-jstl-api = "jakarta.servlet.jsp.jstl:jakarta.servlet.jsp.jstl-api:3.0.2"
 jakarta-websocket-jakarta-websocket-api = { module = "jakarta.websocket:jakarta.websocket-api", version.ref = "jakarta-websocket" }
 jakarta-websocket-jakarta-websocket-client-api = { module = "jakarta.websocket:jakarta.websocket-client-api", version.ref = "jakarta-websocket" }
 jakarta-xml-bind-jakarta-xml-bind-api = "jakarta.xml.bind:jakarta.xml.bind-api:4.0.2"
@@ -68,11 +68,11 @@ org-eclipse-jetty-jetty-server = { module = "org.eclipse.jetty:jetty-server", ve
 org-eclipse-jetty-jetty-servlet = { module = "org.eclipse.jetty:jetty-servlet", version.ref = "org-eclipse-jetty" }
 org-hamcrest = "org.hamcrest:hamcrest:2.2"
 org-hibernate-orm-hibernate-core = "org.hibernate.orm:hibernate-core:6.3.2.Final"
-org-hsqldb = "org.hsqldb:hsqldb:2.7.3"
+org-hsqldb = "org.hsqldb:hsqldb:2.7.4"
 org-jetbrains-kotlin-kotlin-bom = { module = "org.jetbrains.kotlin:kotlin-bom", version.ref = "org-jetbrains-kotlin" }
 org-jetbrains-kotlin-kotlin-gradle-plugin = "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.25"
 org-jetbrains-kotlinx-kotlinx-coroutines-bom = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-bom", version.ref = "org-jetbrains-kotlinx" }
-org-junit-junit-bom = "org.junit:junit-bom:5.10.3"
+org-junit-junit-bom = "org.junit:junit-bom:5.10.5"
 org-mockito-mockito-bom = { module = "org.mockito:mockito-bom", version.ref = "org-mockito" }
 org-opensaml-opensaml-core = { module = "org.opensaml:opensaml-core", version.ref = "org-opensaml" }
 org-opensaml-opensaml-saml-api = { module = "org.opensaml:opensaml-saml-api", version.ref = "org-opensaml" }
@@ -84,8 +84,8 @@ org-seleniumhq-selenium-selenium-support = "org.seleniumhq.selenium:selenium-sup
 org-skyscreamer-jsonassert = "org.skyscreamer:jsonassert:1.5.3"
 org-slf4j-log4j-over-slf4j = "org.slf4j:log4j-over-slf4j:1.7.36"
 org-slf4j-slf4j-api = "org.slf4j:slf4j-api:2.0.16"
-org-springframework-data-spring-data-bom = "org.springframework.data:spring-data-bom:2023.1.9"
-org-springframework-ldap-spring-ldap-core = "org.springframework.ldap:spring-ldap-core:3.2.6"
+org-springframework-data-spring-data-bom = "org.springframework.data:spring-data-bom:2023.1.12"
+org-springframework-ldap-spring-ldap-core = "org.springframework.ldap:spring-ldap-core:3.2.8"
 org-springframework-spring-framework-bom = { module = "org.springframework:spring-framework-bom", version.ref = "org-springframework" }
 org-synchronoss-cloud-nio-multipart-parser = "org.synchronoss.cloud:nio-multipart-parser:1.1.0"

@@ -1,7 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionSha256Sum=544c35d6bd849ae8a5ed0bcea39ba677dc40f49df7d1835561582da2009b961d
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+distributionSha256Sum=31c55713e40233a8303827ceb42ca48a47267a0ad4bab9177123121e71524c26
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.10.2-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#

 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -84,7 +86,8 @@ done
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
 # Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
-APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit

 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -13,6 +13,8 @@
@rem See the License for the specific language governing permissions and
@rem limitations under the License.
@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem

@if "%DEBUG%"=="" @echo off
@rem ##########################################################################
@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2010 the original author or authors.
+ * Copyright 2005-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@

 package org.springframework.security.ldap;

+import java.util.Locale;
+
 import org.springframework.ldap.BadLdapGrammarException;

 /**
@@ -72,7 +74,7 @@ final class LdapEncoder {
 	}

 	protected static String toTwoCharHex(char c) {
-		String raw = Integer.toHexString(c).toUpperCase();
+		String raw = Integer.toHexString(c).toUpperCase(Locale.ENGLISH);
 		return (raw.length() > 1) ? raw : "0" + raw;
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2010 the original author or authors.
+ * Copyright 2005-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@

 package org.springframework.security.ldap.authentication;

+import java.util.Locale;
+
 import org.springframework.ldap.BadLdapGrammarException;

 /**
@@ -72,7 +74,7 @@ final class LdapEncoder {
 	}

 	protected static String toTwoCharHex(char c) {
-		String raw = Integer.toHexString(c).toUpperCase();
+		String raw = Integer.toHexString(c).toUpperCase(Locale.ENGLISH);
 		return (raw.length() > 1) ? raw : "0" + raw;
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import java.util.Collection;
 import java.util.HashMap;
 import java.util.Hashtable;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -144,9 +145,9 @@ public final class ActiveDirectoryLdapAuthenticationProvider extends AbstractLda
 	 */
 	public ActiveDirectoryLdapAuthenticationProvider(String domain, String url, String rootDn) {
 		Assert.isTrue(StringUtils.hasText(url), "Url cannot be empty");
-		this.domain = StringUtils.hasText(domain) ? domain.toLowerCase() : null;
+		this.domain = StringUtils.hasText(domain) ? domain.toLowerCase(Locale.ROOT) : null;
 		this.url = url;
-		this.rootDn = StringUtils.hasText(rootDn) ? rootDn.toLowerCase() : null;
+		this.rootDn = StringUtils.hasText(rootDn) ? rootDn.toLowerCase(Locale.ROOT) : null;
 	}

 	/**
@@ -155,7 +156,7 @@ public final class ActiveDirectoryLdapAuthenticationProvider extends AbstractLda
 	 */
 	public ActiveDirectoryLdapAuthenticationProvider(String domain, String url) {
 		Assert.isTrue(StringUtils.hasText(url), "Url cannot be empty");
-		this.domain = StringUtils.hasText(domain) ? domain.toLowerCase() : null;
+		this.domain = StringUtils.hasText(domain) ? domain.toLowerCase(Locale.ROOT) : null;
 		this.url = url;
 		this.rootDn = (this.domain != null) ? rootDnFromDomain(this.domain) : null;
 	}
@@ -350,7 +351,7 @@ public final class ActiveDirectoryLdapAuthenticationProvider extends AbstractLda
 	}

 	String createBindPrincipal(String username) {
-		if (this.domain == null || username.toLowerCase().endsWith(this.domain)) {
+		if (this.domain == null || username.toLowerCase(Locale.ROOT).endsWith(this.domain)) {
 			return username;
 		}
 		return username + "@" + this.domain;
@@ -20,6 +20,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
@@ -179,7 +180,7 @@ public class DefaultLdapAuthoritiesPopulator implements LdapAuthoritiesPopulator
 				return null;
 			}
 			if (this.convertToUpperCase) {
-				role = role.toUpperCase();
+				role = role.toUpperCase(Locale.ROOT);
 			}
 			return new SimpleGrantedAuthority(this.rolePrefix + role);
 		};
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.ListIterator;
+import java.util.Locale;

 import javax.naming.Context;
 import javax.naming.NameNotFoundException;
@@ -124,7 +125,7 @@ public class LdapUserDetailsManager implements UserDetailsManager {
 		NamingEnumeration<?> ne = roleAttr.getAll();
 		Object group = ne.next();
 		String role = group.toString();
-		return new SimpleGrantedAuthority(this.rolePrefix + role.toUpperCase());
+		return new SimpleGrantedAuthority(this.rolePrefix + role.toUpperCase(Locale.ROOT));
 	};

 	private String[] attributesToRetrieve;
@@ -289,7 +290,7 @@ public class LdapUserDetailsManager implements UserDetailsManager {
 	@Deprecated
 	protected DistinguishedName buildGroupDn(String group) {
 		DistinguishedName dn = new DistinguishedName(this.groupSearchBase);
-		dn.add(this.groupRoleAttributeName, group.toLowerCase());
+		dn.add(this.groupRoleAttributeName, group.toLowerCase(Locale.ROOT));
 		return dn;
 	}

@@ -17,6 +17,7 @@
 package org.springframework.security.ldap.userdetails;

 import java.util.Collection;
+import java.util.Locale;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -127,7 +128,7 @@ public class LdapUserDetailsMapper implements UserDetailsContextMapper {
 	protected GrantedAuthority createAuthority(Object role) {
 		if (role instanceof String) {
 			if (this.convertToUpperCase) {
-				role = ((String) role).toUpperCase();
+				role = ((String) role).toUpperCase(Locale.ROOT);
 			}
 			return new SimpleGrantedAuthority(this.rolePrefix + role);
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.ldap.userdetails;

 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;

@@ -193,7 +194,7 @@ public class NestedLdapAuthoritiesPopulator extends DefaultLdapAuthoritiesPopula
 			}
 			for (String role : roles) {
 				if (isConvertToUpperCase()) {
-					role = role.toUpperCase();
+					role = role.toUpperCase(Locale.ROOT);
 				}
 				role = getRolePrefix() + role;
 				// if the group already exist, we will not search for it's parents again.
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.oauth2.client.web.reactive.function.client;

 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Consumer;
@@ -539,7 +540,7 @@ public final class ServerOAuth2AuthorizedClientExchangeFilterFunction implements
 			// @formatter:off
 			return Stream.of(wwwAuthenticateHeader)
 					.filter((header) -> StringUtils.hasLength(header))
-					.filter((header) -> header.toLowerCase().startsWith("bearer"))
+					.filter((header) -> header.toLowerCase(Locale.ENGLISH).startsWith("bearer"))
 					.map((header) -> header.substring("bearer".length()))
 					.map((header) -> header.split(","))
 					.flatMap(Stream::of)
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.security.oauth2.client.web.reactive.function.client;

 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
@@ -654,7 +655,7 @@ public final class ServletOAuth2AuthorizedClientExchangeFilterFunction implement
 		private Map<String, String> parseAuthParameters(String wwwAuthenticateHeader) {
 			// @formatter:off
 			return Stream.of(wwwAuthenticateHeader).filter((header) -> StringUtils.hasLength(header))
-					.filter((header) -> header.toLowerCase().startsWith("bearer"))
+					.filter((header) -> header.toLowerCase(Locale.ENGLISH).startsWith("bearer"))
 					.map((header) -> header.substring("bearer".length()))
 					.map((header) -> header.split(","))
 					.flatMap(Stream::of)
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -440,7 +440,21 @@ public final class OAuth2AuthorizationRequest implements Serializable {
 			Map<String, Object> parameters = getParameters(); // Not encoded
 			this.parametersConsumer.accept(parameters);
 			MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<>();
-			parameters.forEach((k, v) -> queryParams.set(encodeQueryParam(k), encodeQueryParam(String.valueOf(v)))); // Encoded
+			parameters.forEach((k, v) -> {
+				String key = encodeQueryParam(k);
+				if (v instanceof Iterable) {
+					((Iterable<?>) v).forEach((value) -> queryParams.add(key, encodeQueryParam(String.valueOf(value))));
+				}
+				else if (v != null && v.getClass().isArray()) {
+					Object[] values = (Object[]) v;
+					for (Object value : values) {
+						queryParams.add(key, encodeQueryParam(String.valueOf(value)));
+					}
+				}
+				else {
+					queryParams.set(key, encodeQueryParam(String.valueOf(v)));
+				}
+			});
 			UriBuilder uriBuilder = this.uriBuilderFactory.uriString(this.authorizationUri).queryParams(queryParams);
 			return this.authorizationRequestUriFunction.apply(uriBuilder).toString();
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.security.oauth2.core.endpoint;
 import java.net.URI;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
@@ -319,4 +320,49 @@ public class OAuth2AuthorizationRequestTests {
 						+ "item%20amount=19.95%E2%82%AC&%C3%A2ge=4%C2%BD&item%20name=H%C3%85M%C3%96");
 	}

+	@Test
+	public void buildWhenAdditionalParametersContainsArrayThenProperlyEncoded() {
+		Map<String, Object> additionalParameters = new LinkedHashMap<>();
+		additionalParameters.put("item1", new String[] { "1", "2" });
+		additionalParameters.put("item2", "value2");
+		OAuth2AuthorizationRequest authorizationRequest = TestOAuth2AuthorizationRequests.request()
+			.additionalParameters(additionalParameters)
+			.build();
+		assertThat(authorizationRequest.getAuthorizationRequestUri()).isNotNull();
+		assertThat(authorizationRequest.getAuthorizationRequestUri())
+			.isEqualTo("https://example.com/login/oauth/authorize?response_type=code&client_id=client-id&state=state&"
+					+ "redirect_uri=https://example.com/authorize/oauth2/code/registration-id&"
+					+ "item1=1&item1=2&item2=value2");
+	}
+
+	@Test
+	public void buildWhenAdditionalParametersContainsIterableThenProperlyEncoded() {
+		Map<String, Object> additionalParameters = new LinkedHashMap<>();
+		additionalParameters.put("item1", Arrays.asList("1", "2"));
+		additionalParameters.put("item2", "value2");
+		OAuth2AuthorizationRequest authorizationRequest = TestOAuth2AuthorizationRequests.request()
+			.additionalParameters(additionalParameters)
+			.build();
+		assertThat(authorizationRequest.getAuthorizationRequestUri()).isNotNull();
+		assertThat(authorizationRequest.getAuthorizationRequestUri())
+			.isEqualTo("https://example.com/login/oauth/authorize?response_type=code&client_id=client-id&state=state&"
+					+ "redirect_uri=https://example.com/authorize/oauth2/code/registration-id&"
+					+ "item1=1&item1=2&item2=value2");
+	}
+
+	@Test
+	public void buildWhenAdditionalParametersContainsNullThenAuthorizationRequestUriContainsNull() {
+		Map<String, Object> additionalParameters = new LinkedHashMap<>();
+		additionalParameters.put("item1", null);
+		additionalParameters.put("item2", "value2");
+		OAuth2AuthorizationRequest authorizationRequest = TestOAuth2AuthorizationRequests.request()
+			.additionalParameters(additionalParameters)
+			.build();
+		assertThat(authorizationRequest.getAuthorizationRequestUri()).isNotNull();
+		assertThat(authorizationRequest.getAuthorizationRequestUri())
+			.isEqualTo("https://example.com/login/oauth/authorize?response_type=code&client_id=client-id&state=state&"
+					+ "redirect_uri=https://example.com/authorize/oauth2/code/registration-id&"
+					+ "item1=null&item2=value2");
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -57,13 +57,18 @@ public final class DefaultBearerTokenResolver implements BearerTokenResolver {
 				? resolveFromRequestParameters(request) : null;
 		if (authorizationHeaderToken != null) {
 			if (parameterToken != null) {
-				final BearerTokenError error = BearerTokenErrors
+				BearerTokenError error = BearerTokenErrors
 					.invalidRequest("Found multiple bearer tokens in the request");
 				throw new OAuth2AuthenticationException(error);
 			}
 			return authorizationHeaderToken;
 		}
 		if (parameterToken != null && isParameterTokenEnabledForRequest(request)) {
+			if (!StringUtils.hasText(parameterToken)) {
+				BearerTokenError error = BearerTokenErrors
+					.invalidRequest("The requested token parameter is an empty string");
+				throw new OAuth2AuthenticationException(error);
+			}
 			return parameterToken;
 		}
 		return null;
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -78,6 +78,11 @@ public class ServerBearerTokenAuthenticationConverter implements ServerAuthentic
 			return authorizationHeaderToken;
 		}
 		if (parameterToken != null && isParameterTokenSupportedForRequest(request)) {
+			if (!StringUtils.hasText(parameterToken)) {
+				BearerTokenError error = BearerTokenErrors
+					.invalidRequest("The requested token parameter is an empty string");
+				throw new OAuth2AuthenticationException(error);
+			}
 			return parameterToken;
 		}
 		return null;
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -21,8 +21,11 @@ import java.util.Base64;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;

+import org.springframework.http.HttpStatus;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.server.resource.BearerTokenError;
+import org.springframework.security.oauth2.server.resource.BearerTokenErrorCodes;

 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -258,4 +261,35 @@ public class DefaultBearerTokenResolverTests {
 		assertThat(this.resolver.resolve(request)).isNull();
 	}

+	@Test
+	public void resolveWhenQueryParameterIsPresentAndEmptyStringThenTokenIsNotResolved() {
+		this.resolver.setAllowUriQueryParameter(true);
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.setMethod("GET");
+		request.addParameter("access_token", "");
+		assertThatExceptionOfType(OAuth2AuthenticationException.class).isThrownBy(() -> this.resolver.resolve(request))
+			.withMessageContaining("The requested token parameter is an empty string")
+			.satisfies((e) -> {
+				BearerTokenError error = (BearerTokenError) e.getError();
+				assertThat(error.getErrorCode()).isEqualTo(BearerTokenErrorCodes.INVALID_REQUEST);
+				assertThat(error.getHttpStatus()).isEqualTo(HttpStatus.BAD_REQUEST);
+			});
+	}
+
+	@Test
+	public void resolveWhenFormParameterIsPresentAndEmptyStringThenTokenIsNotResolved() {
+		this.resolver.setAllowFormEncodedBodyParameter(true);
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.setMethod("POST");
+		request.setContentType("application/x-www-form-urlencoded");
+		request.addParameter("access_token", "");
+		assertThatExceptionOfType(OAuth2AuthenticationException.class).isThrownBy(() -> this.resolver.resolve(request))
+			.withMessageContaining("The requested token parameter is an empty string")
+			.satisfies((e) -> {
+				BearerTokenError error = (BearerTokenError) e.getError();
+				assertThat(error.getErrorCode()).isEqualTo(BearerTokenErrorCodes.INVALID_REQUEST);
+				assertThat(error.getHttpStatus()).isEqualTo(HttpStatus.BAD_REQUEST);
+			});
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -187,9 +187,9 @@ public class ServerBearerTokenAuthenticationConverterTests {
 				.isThrownBy(() -> convertToToken(request))
 				.satisfies((ex) -> {
 					BearerTokenError error = (BearerTokenError) ex.getError();
-					assertThat(error.getErrorCode()).isEqualTo(BearerTokenErrorCodes.INVALID_TOKEN);
+					assertThat(error.getErrorCode()).isEqualTo(BearerTokenErrorCodes.INVALID_REQUEST);
 					assertThat(error.getUri()).isEqualTo("https://tools.ietf.org/html/rfc6750#section-3.1");
-					assertThat(error.getHttpStatus()).isEqualTo(HttpStatus.UNAUTHORIZED);
+					assertThat(error.getHttpStatus()).isEqualTo(HttpStatus.BAD_REQUEST);
 				});
 		// @formatter:on
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2022 the original author or authors.
+ * Copyright 2004-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.springframework.security.taglibs.authz;

 import java.io.IOException;
+import java.util.Locale;
 import java.util.Map;

 import jakarta.servlet.ServletContext;
@@ -169,7 +170,7 @@ public abstract class AbstractAuthorizeTag {
 	}

 	public void setMethod(String method) {
-		this.method = (method != null) ? method.toUpperCase() : null;
+		this.method = (method != null) ? method.toUpperCase(Locale.ENGLISH) : null;
 	}

 	private SecurityContext getContext() {
@@ -16,6 +16,8 @@

 package org.springframework.security.web;

+import java.util.Locale;
+
 import jakarta.servlet.ServletRequest;

 import org.springframework.util.Assert;
@@ -45,7 +47,7 @@ public class PortResolverImpl implements PortResolver {
 	@Override
 	public int getServerPort(ServletRequest request) {
 		int serverPort = request.getServerPort();
-		String scheme = request.getScheme().toLowerCase();
+		String scheme = request.getScheme().toLowerCase(Locale.ENGLISH);
 		Integer mappedPort = getMappedPort(serverPort, scheme);
 		return (mappedPort != null) ? mappedPort : serverPort;
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -73,6 +73,9 @@ public class CookieRequestCache implements RequestCache {
 			return null;
 		}
 		String originalURI = decodeCookie(savedRequestCookie.getValue());
+		if (originalURI == null) {
+			return null;
+		}
 		UriComponents uriComponents = UriComponentsBuilder.fromUriString(originalURI).build();
 		DefaultSavedRequest.Builder builder = new DefaultSavedRequest.Builder();
 		int port = getPort(uriComponents);
@@ -122,8 +125,14 @@ public class CookieRequestCache implements RequestCache {
 		return Base64.getEncoder().encodeToString(cookieValue.getBytes());
 	}

-	private static String decodeCookie(String encodedCookieValue) {
-		return new String(Base64.getDecoder().decode(encodedCookieValue.getBytes()));
+	private String decodeCookie(String encodedCookieValue) {
+		try {
+			return new String(Base64.getDecoder().decode(encodedCookieValue.getBytes()));
+		}
+		catch (IllegalArgumentException ex) {
+			this.logger.debug("Failed decode cookie value " + encodedCookieValue);
+			return null;
+		}
 	}

 	private static String getCookiePath(HttpServletRequest request) {
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -20,11 +20,15 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;

-import jakarta.servlet.FilterChain;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;

 import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.server.firewall.HttpStatusExchangeRejectedHandler;
+import org.springframework.security.web.server.firewall.ServerExchangeRejectedException;
+import org.springframework.security.web.server.firewall.ServerExchangeRejectedHandler;
+import org.springframework.security.web.server.firewall.ServerWebExchangeFirewall;
+import org.springframework.security.web.server.firewall.StrictServerWebExchangeFirewall;
 import org.springframework.util.Assert;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
@@ -43,6 +47,10 @@ public class WebFilterChainProxy implements WebFilter {

 	private WebFilterChainDecorator filterChainDecorator = new DefaultWebFilterChainDecorator();

+	private ServerWebExchangeFirewall firewall = new StrictServerWebExchangeFirewall();
+
+	private ServerExchangeRejectedHandler exchangeRejectedHandler = new HttpStatusExchangeRejectedHandler();
+
 	public WebFilterChainProxy(List<SecurityWebFilterChain> filters) {
 		this.filters = filters;
 	}
@@ -53,14 +61,41 @@ public class WebFilterChainProxy implements WebFilter {

 	@Override
 	public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
+		return this.firewall.getFirewalledExchange(exchange)
+			.flatMap((firewalledExchange) -> filterFirewalledExchange(firewalledExchange, chain))
+			.onErrorResume(ServerExchangeRejectedException.class,
+					(rejected) -> this.exchangeRejectedHandler.handle(exchange, rejected).then(Mono.empty()));
+	}
+
+	private Mono<Void> filterFirewalledExchange(ServerWebExchange firewalledExchange, WebFilterChain chain) {
 		return Flux.fromIterable(this.filters)
-			.filterWhen((securityWebFilterChain) -> securityWebFilterChain.matches(exchange))
+			.filterWhen((securityWebFilterChain) -> securityWebFilterChain.matches(firewalledExchange))
 			.next()
-			.switchIfEmpty(
-					Mono.defer(() -> this.filterChainDecorator.decorate(chain).filter(exchange).then(Mono.empty())))
+			.switchIfEmpty(Mono
+				.defer(() -> this.filterChainDecorator.decorate(chain).filter(firewalledExchange).then(Mono.empty())))
 			.flatMap((securityWebFilterChain) -> securityWebFilterChain.getWebFilters().collectList())
 			.map((filters) -> this.filterChainDecorator.decorate(chain, filters))
-			.flatMap((securedChain) -> securedChain.filter(exchange));
+			.flatMap((securedChain) -> securedChain.filter(firewalledExchange));
+	}
+
+	/**
+	 * Protects the application using the provided
+	 * {@link StrictServerWebExchangeFirewall}.
+	 * @param firewall the {@link StrictServerWebExchangeFirewall} to use. Cannot be null.
+	 * @since 6.4
+	 */
+	public void setFirewall(ServerWebExchangeFirewall firewall) {
+		Assert.notNull(firewall, "firewall cannot be null");
+		this.firewall = firewall;
+	}
+
+	/**
+	 * Handles {@link ServerExchangeRejectedException} when the
+	 * {@link ServerWebExchangeFirewall} rejects the provided {@link ServerWebExchange}.
+	 * @param exchangeRejectedHandler the {@link ServerExchangeRejectedHandler} to use.
+	 */
+	public void setExchangeRejectedHandler(ServerExchangeRejectedHandler exchangeRejectedHandler) {
+		this.exchangeRejectedHandler = exchangeRejectedHandler;
 	}

 	/**
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.web.server.firewall;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import reactor.core.publisher.Mono;
+
+import org.springframework.core.log.LogMessage;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A simple implementation of {@link ServerExchangeRejectedHandler} that sends an error
+ * with configurable status code.
+ *
+ * @author Rob Winch
+ * @since 6.4
+ */
+public class HttpStatusExchangeRejectedHandler implements ServerExchangeRejectedHandler {
+
+	private static final Log logger = LogFactory.getLog(HttpStatusExchangeRejectedHandler.class);
+
+	private final HttpStatus status;
+
+	/**
+	 * Constructs an instance which uses {@code 400} as response code.
+	 */
+	public HttpStatusExchangeRejectedHandler() {
+		this(HttpStatus.BAD_REQUEST);
+	}
+
+	/**
+	 * Constructs an instance which uses a configurable http code as response.
+	 * @param status http status code to use
+	 */
+	public HttpStatusExchangeRejectedHandler(HttpStatus status) {
+		this.status = status;
+	}
+
+	@Override
+	public Mono<Void> handle(ServerWebExchange exchange,
+			ServerExchangeRejectedException serverExchangeRejectedException) {
+		return Mono.fromRunnable(() -> {
+			logger.debug(
+					LogMessage.format("Rejecting request due to: %s", serverExchangeRejectedException.getMessage()),
+					serverExchangeRejectedException);
+			exchange.getResponse().setStatusCode(this.status);
+		});
+	}
+
+}
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.web.server.firewall;
+
+/**
+ * Thrown when a {@link org.springframework.web.server.ServerWebExchange} is rejected.
+ *
+ * @author Rob Winch
+ * @since 6.4
+ */
+public class ServerExchangeRejectedException extends RuntimeException {
+
+	public ServerExchangeRejectedException(String message) {
+		super(message);
+	}
+
+}
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.web.server.firewall;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * Handles {@link ServerExchangeRejectedException} thrown by
+ * {@link ServerWebExchangeFirewall}.
+ *
+ * @author Rob Winch
+ * @since 6.4
+ */
+public interface ServerExchangeRejectedHandler {
+
+	/**
+	 * Handles an request rejected failure.
+	 * @param exchange the {@link ServerWebExchange} that was rejected
+	 * @param serverExchangeRejectedException that caused the invocation
+	 */
+	Mono<Void> handle(ServerWebExchange exchange, ServerExchangeRejectedException serverExchangeRejectedException);
+
+}
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.web.server.firewall;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * Interface which can be used to reject potentially dangerous requests and/or wrap them
+ * to control their behaviour.
+ *
+ * @author Rob Winch
+ * @since 6.4
+ */
+public interface ServerWebExchangeFirewall {
+
+	/**
+	 * An implementation of {@link StrictServerWebExchangeFirewall} that does nothing.
+	 * This is considered insecure and not recommended.
+	 */
+	ServerWebExchangeFirewall INSECURE_NOOP = (exchange) -> Mono.just(exchange);
+
+	/**
+	 * Get a {@link ServerWebExchange} that has firewall rules applied to it.
+	 * @param exchange the {@link ServerWebExchange} to apply firewall rules to.
+	 * @return the {@link ServerWebExchange} that has firewall rules applied to it.
+	 * @throws ServerExchangeRejectedException when a rule is broken.
+	 */
+	Mono<ServerWebExchange> getFirewalledExchange(ServerWebExchange exchange);
+
+}
@@ -0,0 +1,790 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.web.server.firewall;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.util.Assert;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.ServerWebExchangeDecorator;
+
+/**
+ * <p>
+ * A strict implementation of {@link ServerWebExchangeFirewall} that rejects any
+ * suspicious requests with a {@link ServerExchangeRejectedException}.
+ * </p>
+ * <p>
+ * The following rules are applied to the firewall:
+ * </p>
+ * <ul>
+ * <li>Rejects HTTP methods that are not allowed. This specified to block
+ * <a href="https://www.owasp.org/index.php/Test_HTTP_Methods_(OTG-CONFIG-006)">HTTP Verb
+ * tampering and XST attacks</a>. See {@link #setAllowedHttpMethods(Collection)}</li>
+ * <li>Rejects URLs that are not normalized to avoid bypassing security constraints. There
+ * is no way to disable this as it is considered extremely risky to disable this
+ * constraint. A few options to allow this behavior is to normalize the request prior to
+ * the firewall or using
+ * {@link org.springframework.security.web.firewall.DefaultHttpFirewall} instead. Please
+ * keep in mind that normalizing the request is fragile and why requests are rejected
+ * rather than normalized.</li>
+ * <li>Rejects URLs that contain characters that are not printable ASCII characters. There
+ * is no way to disable this as it is considered extremely risky to disable this
+ * constraint.</li>
+ * <li>Rejects URLs that contain semicolons. See {@link #setAllowSemicolon(boolean)}</li>
+ * <li>Rejects URLs that contain a URL encoded slash. See
+ * {@link #setAllowUrlEncodedSlash(boolean)}</li>
+ * <li>Rejects URLs that contain a backslash. See {@link #setAllowBackSlash(boolean)}</li>
+ * <li>Rejects URLs that contain a null character. See {@link #setAllowNull(boolean)}</li>
+ * <li>Rejects URLs that contain a URL encoded percent. See
+ * {@link #setAllowUrlEncodedPercent(boolean)}</li>
+ * <li>Rejects hosts that are not allowed. See {@link #setAllowedHostnames(Predicate)}
+ * </li>
+ * <li>Reject headers names that are not allowed. See
+ * {@link #setAllowedHeaderNames(Predicate)}</li>
+ * <li>Reject headers values that are not allowed. See
+ * {@link #setAllowedHeaderValues(Predicate)}</li>
+ * <li>Reject parameter names that are not allowed. See
+ * {@link #setAllowedParameterNames(Predicate)}</li>
+ * <li>Reject parameter values that are not allowed. See
+ * {@link #setAllowedParameterValues(Predicate)}</li>
+ * </ul>
+ *
+ * @author Rob Winch
+ * @since 6.4
+ */
+public class StrictServerWebExchangeFirewall implements ServerWebExchangeFirewall {
+
+	/**
+	 * Used to specify to {@link #setAllowedHttpMethods(Collection)} that any HTTP method
+	 * should be allowed.
+	 */
+	private static final Set<HttpMethod> ALLOW_ANY_HTTP_METHOD = Collections.emptySet();
+
+	private static final String ENCODED_PERCENT = "%25";
+
+	private static final String PERCENT = "%";
+
+	private static final List<String> FORBIDDEN_ENCODED_PERIOD = Collections
+		.unmodifiableList(Arrays.asList("%2e", "%2E"));
+
+	private static final List<String> FORBIDDEN_SEMICOLON = Collections
+		.unmodifiableList(Arrays.asList(";", "%3b", "%3B"));
+
+	private static final List<String> FORBIDDEN_FORWARDSLASH = Collections
+		.unmodifiableList(Arrays.asList("%2f", "%2F"));
+
+	private static final List<String> FORBIDDEN_DOUBLE_FORWARDSLASH = Collections
+		.unmodifiableList(Arrays.asList("//", "%2f%2f", "%2f%2F", "%2F%2f", "%2F%2F"));
+
+	private static final List<String> FORBIDDEN_BACKSLASH = Collections
+		.unmodifiableList(Arrays.asList("\\", "%5c", "%5C"));
+
+	private static final List<String> FORBIDDEN_NULL = Collections.unmodifiableList(Arrays.asList("\0", "%00"));
+
+	private static final List<String> FORBIDDEN_LF = Collections.unmodifiableList(Arrays.asList("\n", "%0a", "%0A"));
+
+	private static final List<String> FORBIDDEN_CR = Collections.unmodifiableList(Arrays.asList("\r", "%0d", "%0D"));
+
+	private static final List<String> FORBIDDEN_LINE_SEPARATOR = Collections.unmodifiableList(Arrays.asList("\u2028"));
+
+	private static final List<String> FORBIDDEN_PARAGRAPH_SEPARATOR = Collections
+		.unmodifiableList(Arrays.asList("\u2029"));
+
+	private Set<String> encodedUrlBlocklist = new HashSet<>();
+
+	private Set<String> decodedUrlBlocklist = new HashSet<>();
+
+	private Set<HttpMethod> allowedHttpMethods = createDefaultAllowedHttpMethods();
+
+	private Predicate<String> allowedHostnames = (hostname) -> true;
+
+	private static final Pattern ASSIGNED_AND_NOT_ISO_CONTROL_PATTERN = Pattern
+		.compile("[\\p{IsAssigned}&&[^\\p{IsControl}]]*");
+
+	private static final Predicate<String> ASSIGNED_AND_NOT_ISO_CONTROL_PREDICATE = (
+			s) -> ASSIGNED_AND_NOT_ISO_CONTROL_PATTERN.matcher(s).matches();
+
+	private static final Pattern HEADER_VALUE_PATTERN = Pattern.compile("[\\p{IsAssigned}&&[[^\\p{IsControl}]||\\t]]*");
+
+	private static final Predicate<String> HEADER_VALUE_PREDICATE = (s) -> s == null
+			|| HEADER_VALUE_PATTERN.matcher(s).matches();
+
+	private Predicate<String> allowedHeaderNames = ALLOWED_HEADER_NAMES;
+
+	public static final Predicate<String> ALLOWED_HEADER_NAMES = ASSIGNED_AND_NOT_ISO_CONTROL_PREDICATE;
+
+	private Predicate<String> allowedHeaderValues = ALLOWED_HEADER_VALUES;
+
+	public static final Predicate<String> ALLOWED_HEADER_VALUES = HEADER_VALUE_PREDICATE;
+
+	private Predicate<String> allowedParameterNames = ALLOWED_PARAMETER_NAMES;
+
+	public static final Predicate<String> ALLOWED_PARAMETER_NAMES = ASSIGNED_AND_NOT_ISO_CONTROL_PREDICATE;
+
+	private Predicate<String> allowedParameterValues = ALLOWED_PARAMETER_VALUES;
+
+	public static final Predicate<String> ALLOWED_PARAMETER_VALUES = (value) -> true;
+
+	public StrictServerWebExchangeFirewall() {
+		urlBlocklistsAddAll(FORBIDDEN_SEMICOLON);
+		urlBlocklistsAddAll(FORBIDDEN_FORWARDSLASH);
+		urlBlocklistsAddAll(FORBIDDEN_DOUBLE_FORWARDSLASH);
+		urlBlocklistsAddAll(FORBIDDEN_BACKSLASH);
+		urlBlocklistsAddAll(FORBIDDEN_NULL);
+		urlBlocklistsAddAll(FORBIDDEN_LF);
+		urlBlocklistsAddAll(FORBIDDEN_CR);
+
+		this.encodedUrlBlocklist.add(ENCODED_PERCENT);
+		this.encodedUrlBlocklist.addAll(FORBIDDEN_ENCODED_PERIOD);
+		this.decodedUrlBlocklist.add(PERCENT);
+		this.decodedUrlBlocklist.addAll(FORBIDDEN_LINE_SEPARATOR);
+		this.decodedUrlBlocklist.addAll(FORBIDDEN_PARAGRAPH_SEPARATOR);
+	}
+
+	public Set<String> getEncodedUrlBlocklist() {
+		return this.encodedUrlBlocklist;
+	}
+
+	public Set<String> getDecodedUrlBlocklist() {
+		return this.decodedUrlBlocklist;
+	}
+
+	@Override
+	public Mono<ServerWebExchange> getFirewalledExchange(ServerWebExchange exchange) {
+		return Mono.fromCallable(() -> {
+			ServerHttpRequest request = exchange.getRequest();
+			rejectForbiddenHttpMethod(request);
+			rejectedBlocklistedUrls(request);
+			rejectedUntrustedHosts(request);
+			if (!isNormalized(request)) {
+				throw new ServerExchangeRejectedException(
+						"The request was rejected because the URL was not normalized");
+			}
+
+			exchange.getResponse().beforeCommit(() -> Mono.fromRunnable(() -> {
+				ServerHttpResponse response = exchange.getResponse();
+				HttpHeaders headers = response.getHeaders();
+				for (Map.Entry<String, List<String>> header : headers.entrySet()) {
+					String headerName = header.getKey();
+					List<String> headerValues = header.getValue();
+					for (String headerValue : headerValues) {
+						validateCrlf(headerName, headerValue);
+					}
+				}
+			}));
+			return new StrictFirewallServerWebExchange(exchange);
+		});
+	}
+
+	private static void validateCrlf(String name, String value) {
+		Assert.isTrue(!hasCrlf(name) && !hasCrlf(value), () -> "Invalid characters (CR/LF) in header " + name);
+	}
+
+	private static boolean hasCrlf(String value) {
+		return value != null && (value.indexOf('\n') != -1 || value.indexOf('\r') != -1);
+	}
+
+	/**
+	 * Sets if any HTTP method is allowed. If this set to true, then no validation on the
+	 * HTTP method will be performed. This can open the application up to
+	 * <a href="https://www.owasp.org/index.php/Test_HTTP_Methods_(OTG-CONFIG-006)"> HTTP
+	 * Verb tampering and XST attacks</a>
+	 * @param unsafeAllowAnyHttpMethod if true, disables HTTP method validation, else
+	 * resets back to the defaults. Default is false.
+	 * @since 5.1
+	 * @see #setAllowedHttpMethods(Collection)
+	 */
+	public void setUnsafeAllowAnyHttpMethod(boolean unsafeAllowAnyHttpMethod) {
+		this.allowedHttpMethods = unsafeAllowAnyHttpMethod ? ALLOW_ANY_HTTP_METHOD : createDefaultAllowedHttpMethods();
+	}
+
+	/**
+	 * <p>
+	 * Determines which HTTP methods should be allowed. The default is to allow "DELETE",
+	 * "GET", "HEAD", "OPTIONS", "PATCH", "POST", and "PUT".
+	 * </p>
+	 * @param allowedHttpMethods the case-sensitive collection of HTTP methods that are
+	 * allowed.
+	 * @since 5.1
+	 * @see #setUnsafeAllowAnyHttpMethod(boolean)
+	 */
+	public void setAllowedHttpMethods(Collection<HttpMethod> allowedHttpMethods) {
+		Assert.notNull(allowedHttpMethods, "allowedHttpMethods cannot be null");
+		this.allowedHttpMethods = (allowedHttpMethods != ALLOW_ANY_HTTP_METHOD) ? new HashSet<>(allowedHttpMethods)
+				: ALLOW_ANY_HTTP_METHOD;
+	}
+
+	/**
+	 * <p>
+	 * Determines if semicolon is allowed in the URL (i.e. matrix variables). The default
+	 * is to disable this behavior because it is a common way of attempting to perform
+	 * <a href="https://www.owasp.org/index.php/Reflected_File_Download">Reflected File
+	 * Download Attacks</a>. It is also the source of many exploits which bypass URL based
+	 * security.
+	 * </p>
+	 * <p>
+	 * For example, the following CVEs are a subset of the issues related to ambiguities
+	 * in the Servlet Specification on how to treat semicolons that led to CVEs:
+	 * </p>
+	 * <ul>
+	 * <li><a href="https://pivotal.io/security/cve-2016-5007">cve-2016-5007</a></li>
+	 * <li><a href="https://pivotal.io/security/cve-2016-9879">cve-2016-9879</a></li>
+	 * <li><a href="https://pivotal.io/security/cve-2018-1199">cve-2018-1199</a></li>
+	 * </ul>
+	 *
+	 * <p>
+	 * If you are wanting to allow semicolons, please reconsider as it is a very common
+	 * source of security bypasses. A few common reasons users want semicolons and
+	 * alternatives are listed below:
+	 * </p>
+	 * <ul>
+	 * <li>Including the JSESSIONID in the path - You should not include session id (or
+	 * any sensitive information) in a URL as it can lead to leaking. Instead use Cookies.
+	 * </li>
+	 * <li>Matrix Variables - Users wanting to leverage Matrix Variables should consider
+	 * using HTTP parameters instead.</li>
+	 * </ul>
+	 * @param allowSemicolon should semicolons be allowed in the URL. Default is false
+	 */
+	public void setAllowSemicolon(boolean allowSemicolon) {
+		if (allowSemicolon) {
+			urlBlocklistsRemoveAll(FORBIDDEN_SEMICOLON);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_SEMICOLON);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines if a slash "/" that is URL encoded "%2F" should be allowed in the path
+	 * or not. The default is to not allow this behavior because it is a common way to
+	 * bypass URL based security.
+	 * </p>
+	 * <p>
+	 * For example, due to ambiguities in the servlet specification, the value is not
+	 * parsed consistently which results in different values in {@code HttpServletRequest}
+	 * path related values which allow bypassing certain security constraints.
+	 * </p>
+	 * @param allowUrlEncodedSlash should a slash "/" that is URL encoded "%2F" be allowed
+	 * in the path or not. Default is false.
+	 */
+	public void setAllowUrlEncodedSlash(boolean allowUrlEncodedSlash) {
+		if (allowUrlEncodedSlash) {
+			urlBlocklistsRemoveAll(FORBIDDEN_FORWARDSLASH);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_FORWARDSLASH);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines if double slash "//" that is URL encoded "%2F%2F" should be allowed in
+	 * the path or not. The default is to not allow.
+	 * </p>
+	 * @param allowUrlEncodedDoubleSlash should a slash "//" that is URL encoded "%2F%2F"
+	 * be allowed in the path or not. Default is false.
+	 */
+	public void setAllowUrlEncodedDoubleSlash(boolean allowUrlEncodedDoubleSlash) {
+		if (allowUrlEncodedDoubleSlash) {
+			urlBlocklistsRemoveAll(FORBIDDEN_DOUBLE_FORWARDSLASH);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_DOUBLE_FORWARDSLASH);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines if a period "." that is URL encoded "%2E" should be allowed in the path
+	 * or not. The default is to not allow this behavior because it is a frequent source
+	 * of security exploits.
+	 * </p>
+	 * <p>
+	 * For example, due to ambiguities in the servlet specification a URL encoded period
+	 * might lead to bypassing security constraints through a directory traversal attack.
+	 * This is because the path is not parsed consistently which results in different
+	 * values in {@code HttpServletRequest} path related values which allow bypassing
+	 * certain security constraints.
+	 * </p>
+	 * @param allowUrlEncodedPeriod should a period "." that is URL encoded "%2E" be
+	 * allowed in the path or not. Default is false.
+	 */
+	public void setAllowUrlEncodedPeriod(boolean allowUrlEncodedPeriod) {
+		if (allowUrlEncodedPeriod) {
+			this.encodedUrlBlocklist.removeAll(FORBIDDEN_ENCODED_PERIOD);
+		}
+		else {
+			this.encodedUrlBlocklist.addAll(FORBIDDEN_ENCODED_PERIOD);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines if a backslash "\" or a URL encoded backslash "%5C" should be allowed in
+	 * the path or not. The default is not to allow this behavior because it is a frequent
+	 * source of security exploits.
+	 * </p>
+	 * <p>
+	 * For example, due to ambiguities in the servlet specification a URL encoded period
+	 * might lead to bypassing security constraints through a directory traversal attack.
+	 * This is because the path is not parsed consistently which results in different
+	 * values in {@code HttpServletRequest} path related values which allow bypassing
+	 * certain security constraints.
+	 * </p>
+	 * @param allowBackSlash a backslash "\" or a URL encoded backslash "%5C" be allowed
+	 * in the path or not. Default is false
+	 */
+	public void setAllowBackSlash(boolean allowBackSlash) {
+		if (allowBackSlash) {
+			urlBlocklistsRemoveAll(FORBIDDEN_BACKSLASH);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_BACKSLASH);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines if a null "\0" or a URL encoded nul "%00" should be allowed in the path
+	 * or not. The default is not to allow this behavior because it is a frequent source
+	 * of security exploits.
+	 * </p>
+	 * @param allowNull a null "\0" or a URL encoded null "%00" be allowed in the path or
+	 * not. Default is false
+	 * @since 5.4
+	 */
+	public void setAllowNull(boolean allowNull) {
+		if (allowNull) {
+			urlBlocklistsRemoveAll(FORBIDDEN_NULL);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_NULL);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines if a percent "%" that is URL encoded "%25" should be allowed in the path
+	 * or not. The default is not to allow this behavior because it is a frequent source
+	 * of security exploits.
+	 * </p>
+	 * <p>
+	 * For example, this can lead to exploits that involve double URL encoding that lead
+	 * to bypassing security constraints.
+	 * </p>
+	 * @param allowUrlEncodedPercent if a percent "%" that is URL encoded "%25" should be
+	 * allowed in the path or not. Default is false
+	 */
+	public void setAllowUrlEncodedPercent(boolean allowUrlEncodedPercent) {
+		if (allowUrlEncodedPercent) {
+			this.encodedUrlBlocklist.remove(ENCODED_PERCENT);
+			this.decodedUrlBlocklist.remove(PERCENT);
+		}
+		else {
+			this.encodedUrlBlocklist.add(ENCODED_PERCENT);
+			this.decodedUrlBlocklist.add(PERCENT);
+		}
+	}
+
+	/**
+	 * Determines if a URL encoded Carriage Return is allowed in the path or not. The
+	 * default is not to allow this behavior because it is a frequent source of security
+	 * exploits.
+	 * @param allowUrlEncodedCarriageReturn if URL encoded Carriage Return is allowed in
+	 * the URL or not. Default is false.
+	 */
+	public void setAllowUrlEncodedCarriageReturn(boolean allowUrlEncodedCarriageReturn) {
+		if (allowUrlEncodedCarriageReturn) {
+			urlBlocklistsRemoveAll(FORBIDDEN_CR);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_CR);
+		}
+	}
+
+	/**
+	 * Determines if a URL encoded Line Feed is allowed in the path or not. The default is
+	 * not to allow this behavior because it is a frequent source of security exploits.
+	 * @param allowUrlEncodedLineFeed if URL encoded Line Feed is allowed in the URL or
+	 * not. Default is false.
+	 */
+	public void setAllowUrlEncodedLineFeed(boolean allowUrlEncodedLineFeed) {
+		if (allowUrlEncodedLineFeed) {
+			urlBlocklistsRemoveAll(FORBIDDEN_LF);
+		}
+		else {
+			urlBlocklistsAddAll(FORBIDDEN_LF);
+		}
+	}
+
+	/**
+	 * Determines if a URL encoded paragraph separator is allowed in the path or not. The
+	 * default is not to allow this behavior because it is a frequent source of security
+	 * exploits.
+	 * @param allowUrlEncodedParagraphSeparator if URL encoded paragraph separator is
+	 * allowed in the URL or not. Default is false.
+	 */
+	public void setAllowUrlEncodedParagraphSeparator(boolean allowUrlEncodedParagraphSeparator) {
+		if (allowUrlEncodedParagraphSeparator) {
+			this.decodedUrlBlocklist.removeAll(FORBIDDEN_PARAGRAPH_SEPARATOR);
+		}
+		else {
+			this.decodedUrlBlocklist.addAll(FORBIDDEN_PARAGRAPH_SEPARATOR);
+		}
+	}
+
+	/**
+	 * Determines if a URL encoded line separator is allowed in the path or not. The
+	 * default is not to allow this behavior because it is a frequent source of security
+	 * exploits.
+	 * @param allowUrlEncodedLineSeparator if URL encoded line separator is allowed in the
+	 * URL or not. Default is false.
+	 */
+	public void setAllowUrlEncodedLineSeparator(boolean allowUrlEncodedLineSeparator) {
+		if (allowUrlEncodedLineSeparator) {
+			this.decodedUrlBlocklist.removeAll(FORBIDDEN_LINE_SEPARATOR);
+		}
+		else {
+			this.decodedUrlBlocklist.addAll(FORBIDDEN_LINE_SEPARATOR);
+		}
+	}
+
+	/**
+	 * <p>
+	 * Determines which header names should be allowed. The default is to reject header
+	 * names that contain ISO control characters and characters that are not defined.
+	 * </p>
+	 * @param allowedHeaderNames the predicate for testing header names
+	 * @since 5.4
+	 * @see Character#isISOControl(int)
+	 * @see Character#isDefined(int)
+	 */
+	public void setAllowedHeaderNames(Predicate<String> allowedHeaderNames) {
+		Assert.notNull(allowedHeaderNames, "allowedHeaderNames cannot be null");
+		this.allowedHeaderNames = allowedHeaderNames;
+	}
+
+	/**
+	 * <p>
+	 * Determines which header values should be allowed. The default is to reject header
+	 * values that contain ISO control characters and characters that are not defined.
+	 * </p>
+	 * @param allowedHeaderValues the predicate for testing hostnames
+	 * @since 5.4
+	 * @see Character#isISOControl(int)
+	 * @see Character#isDefined(int)
+	 */
+	public void setAllowedHeaderValues(Predicate<String> allowedHeaderValues) {
+		Assert.notNull(allowedHeaderValues, "allowedHeaderValues cannot be null");
+		this.allowedHeaderValues = allowedHeaderValues;
+	}
+
+	/**
+	 * Determines which parameter names should be allowed. The default is to reject header
+	 * names that contain ISO control characters and characters that are not defined.
+	 * @param allowedParameterNames the predicate for testing parameter names
+	 * @since 5.4
+	 * @see Character#isISOControl(int)
+	 * @see Character#isDefined(int)
+	 */
+	public void setAllowedParameterNames(Predicate<String> allowedParameterNames) {
+		Assert.notNull(allowedParameterNames, "allowedParameterNames cannot be null");
+		this.allowedParameterNames = allowedParameterNames;
+	}
+
+	/**
+	 * <p>
+	 * Determines which parameter values should be allowed. The default is to allow any
+	 * parameter value.
+	 * </p>
+	 * @param allowedParameterValues the predicate for testing parameter values
+	 * @since 5.4
+	 */
+	public void setAllowedParameterValues(Predicate<String> allowedParameterValues) {
+		Assert.notNull(allowedParameterValues, "allowedParameterValues cannot be null");
+		this.allowedParameterValues = allowedParameterValues;
+	}
+
+	/**
+	 * <p>
+	 * Determines which hostnames should be allowed. The default is to allow any hostname.
+	 * </p>
+	 * @param allowedHostnames the predicate for testing hostnames
+	 * @since 5.2
+	 */
+	public void setAllowedHostnames(Predicate<String> allowedHostnames) {
+		Assert.notNull(allowedHostnames, "allowedHostnames cannot be null");
+		this.allowedHostnames = allowedHostnames;
+	}
+
+	private void urlBlocklistsAddAll(Collection<String> values) {
+		this.encodedUrlBlocklist.addAll(values);
+		this.decodedUrlBlocklist.addAll(values);
+	}
+
+	private void urlBlocklistsRemoveAll(Collection<String> values) {
+		this.encodedUrlBlocklist.removeAll(values);
+		this.decodedUrlBlocklist.removeAll(values);
+	}
+
+	private void rejectNonPrintableAsciiCharactersInFieldName(String toCheck, String propertyName) {
+		if (!containsOnlyPrintableAsciiCharacters(toCheck)) {
+			throw new ServerExchangeRejectedException(String
+				.format("The %s was rejected because it can only contain printable ASCII characters.", propertyName));
+		}
+	}
+
+	private void rejectForbiddenHttpMethod(ServerHttpRequest request) {
+		if (this.allowedHttpMethods == ALLOW_ANY_HTTP_METHOD) {
+			return;
+		}
+		if (!this.allowedHttpMethods.contains(request.getMethod())) {
+			throw new ServerExchangeRejectedException(
+					"The request was rejected because the HTTP method \"" + request.getMethod()
+							+ "\" was not included within the list of allowed HTTP methods " + this.allowedHttpMethods);
+		}
+	}
+
+	private void rejectedBlocklistedUrls(ServerHttpRequest request) {
+		for (String forbidden : this.encodedUrlBlocklist) {
+			if (encodedUrlContains(request, forbidden)) {
+				throw new ServerExchangeRejectedException(
+						"The request was rejected because the URL contained a potentially malicious String \""
+								+ forbidden + "\"");
+			}
+		}
+		for (String forbidden : this.decodedUrlBlocklist) {
+			if (decodedUrlContains(request, forbidden)) {
+				throw new ServerExchangeRejectedException(
+						"The request was rejected because the URL contained a potentially malicious String \""
+								+ forbidden + "\"");
+			}
+		}
+	}
+
+	private void rejectedUntrustedHosts(ServerHttpRequest request) {
+		String hostName = request.getURI().getHost();
+		if (hostName != null && !this.allowedHostnames.test(hostName)) {
+			throw new ServerExchangeRejectedException(
+					"The request was rejected because the domain " + hostName + " is untrusted.");
+		}
+	}
+
+	private static Set<HttpMethod> createDefaultAllowedHttpMethods() {
+		Set<HttpMethod> result = new HashSet<>();
+		result.add(HttpMethod.DELETE);
+		result.add(HttpMethod.GET);
+		result.add(HttpMethod.HEAD);
+		result.add(HttpMethod.OPTIONS);
+		result.add(HttpMethod.PATCH);
+		result.add(HttpMethod.POST);
+		result.add(HttpMethod.PUT);
+		return result;
+	}
+
+	private boolean isNormalized(ServerHttpRequest request) {
+		if (!isNormalized(request.getPath().value())) {
+			return false;
+		}
+		if (!isNormalized(request.getURI().getRawPath())) {
+			return false;
+		}
+		if (!isNormalized(request.getURI().getPath())) {
+			return false;
+		}
+		return true;
+	}
+
+	private void validateAllowedHeaderName(String headerNames) {
+		if (!StrictServerWebExchangeFirewall.this.allowedHeaderNames.test(headerNames)) {
+			throw new ServerExchangeRejectedException(
+					"The request was rejected because the header name \"" + headerNames + "\" is not allowed.");
+		}
+	}
+
+	private void validateAllowedHeaderValue(Object key, String value) {
+		if (!StrictServerWebExchangeFirewall.this.allowedHeaderValues.test(value)) {
+			throw new ServerExchangeRejectedException("The request was rejected because the header: \"" + key
+					+ " \" has a value \"" + value + "\" that is not allowed.");
+		}
+	}
+
+	private void validateAllowedParameterName(String name) {
+		if (!StrictServerWebExchangeFirewall.this.allowedParameterNames.test(name)) {
+			throw new ServerExchangeRejectedException(
+					"The request was rejected because the parameter name \"" + name + "\" is not allowed.");
+		}
+	}
+
+	private void validateAllowedParameterValue(String name, String value) {
+		if (!StrictServerWebExchangeFirewall.this.allowedParameterValues.test(value)) {
+			throw new ServerExchangeRejectedException("The request was rejected because the parameter: \"" + name
+					+ " \" has a value \"" + value + "\" that is not allowed.");
+		}
+	}
+
+	private static boolean encodedUrlContains(ServerHttpRequest request, String value) {
+		if (valueContains(request.getPath().value(), value)) {
+			return true;
+		}
+		return valueContains(request.getURI().getRawPath(), value);
+	}
+
+	private static boolean decodedUrlContains(ServerHttpRequest request, String value) {
+		return valueContains(request.getURI().getPath(), value);
+	}
+
+	private static boolean containsOnlyPrintableAsciiCharacters(String uri) {
+		if (uri == null) {
+			return true;
+		}
+		int length = uri.length();
+		for (int i = 0; i < length; i++) {
+			char ch = uri.charAt(i);
+			if (ch < '\u0020' || ch > '\u007e') {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	private static boolean valueContains(String value, String contains) {
+		return value != null && value.contains(contains);
+	}
+
+	/**
+	 * Checks whether a path is normalized (doesn't contain path traversal sequences like
+	 * "./", "/../" or "/.")
+	 * @param path the path to test
+	 * @return true if the path doesn't contain any path-traversal character sequences.
+	 */
+	private static boolean isNormalized(String path) {
+		if (path == null) {
+			return true;
+		}
+		for (int i = path.length(); i > 0;) {
+			int slashIndex = path.lastIndexOf('/', i - 1);
+			int gap = i - slashIndex;
+			if (gap == 2 && path.charAt(slashIndex + 1) == '.') {
+				return false; // ".", "/./" or "/."
+			}
+			if (gap == 3 && path.charAt(slashIndex + 1) == '.' && path.charAt(slashIndex + 2) == '.') {
+				return false;
+			}
+			i = slashIndex;
+		}
+		return true;
+	}
+
+	private final class StrictFirewallServerWebExchange extends ServerWebExchangeDecorator {
+
+		private StrictFirewallServerWebExchange(ServerWebExchange delegate) {
+			super(delegate);
+		}
+
+		@Override
+		public ServerHttpRequest getRequest() {
+			return new StrictFirewallHttpRequest(super.getRequest());
+		}
+
+		private final class StrictFirewallHttpRequest extends ServerHttpRequestDecorator {
+
+			private StrictFirewallHttpRequest(ServerHttpRequest delegate) {
+				super(delegate);
+			}
+
+			@Override
+			public HttpHeaders getHeaders() {
+				return new StrictFirewallHttpHeaders(super.getHeaders());
+			}
+
+			@Override
+			public MultiValueMap<String, String> getQueryParams() {
+				MultiValueMap<String, String> queryParams = super.getQueryParams();
+				for (Map.Entry<String, List<String>> paramEntry : queryParams.entrySet()) {
+					String paramName = paramEntry.getKey();
+					validateAllowedParameterName(paramName);
+					for (String paramValue : paramEntry.getValue()) {
+						validateAllowedParameterValue(paramName, paramValue);
+					}
+				}
+				return queryParams;
+			}
+
+			private final class StrictFirewallHttpHeaders extends HttpHeaders {
+
+				private StrictFirewallHttpHeaders(HttpHeaders delegate) {
+					super(delegate);
+				}
+
+				@Override
+				public String getFirst(String headerName) {
+					validateAllowedHeaderName(headerName);
+					String headerValue = super.getFirst(headerName);
+					validateAllowedHeaderValue(headerName, headerValue);
+					return headerValue;
+				}
+
+				@Override
+				public List<String> get(Object key) {
+					if (key instanceof String headerName) {
+						validateAllowedHeaderName(headerName);
+					}
+					List<String> headerValues = super.get(key);
+					if (headerValues == null) {
+						return headerValues;
+					}
+					for (String headerValue : headerValues) {
+						validateAllowedHeaderValue(key, headerValue);
+					}
+					return headerValues;
+				}
+
+				@Override
+				public Set<String> keySet() {
+					Set<String> headerNames = super.keySet();
+					for (String headerName : headerNames) {
+						validateAllowedHeaderName(headerName);
+					}
+					return headerNames;
+				}
+
+			}
+
+		}
+
+	}
+
+}
@@ -16,6 +16,7 @@

 package org.springframework.security.web.util;

+import java.util.Locale;
 import java.util.regex.Pattern;

 import jakarta.servlet.http.HttpServletRequest;
@@ -49,7 +50,7 @@ public final class UrlUtils {
 	 */
 	public static String buildFullRequestUrl(String scheme, String serverName, int serverPort, String requestURI,
 			String queryString) {
-		scheme = scheme.toLowerCase();
+		scheme = scheme.toLowerCase(Locale.ENGLISH);
 		StringBuilder url = new StringBuilder();
 		url.append(scheme).append("://").append(serverName);
 		// Only add port if not default
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.springframework.security.web.util.matcher;

 import java.util.Collections;
+import java.util.Locale;
 import java.util.Map;

 import jakarta.servlet.http.HttpServletRequest;
@@ -303,7 +304,7 @@ public final class AntPathRequestMatcher implements RequestMatcher, RequestVaria

 		private SubpathMatcher(String subpath, boolean caseSensitive) {
 			Assert.isTrue(!subpath.contains("*"), "subpath cannot contain \"*\"");
-			this.subpath = caseSensitive ? subpath : subpath.toLowerCase();
+			this.subpath = caseSensitive ? subpath : subpath.toLowerCase(Locale.ROOT);
 			this.length = subpath.length();
 			this.caseSensitive = caseSensitive;
 		}
@@ -311,7 +312,7 @@ public final class AntPathRequestMatcher implements RequestMatcher, RequestVaria
 		@Override
 		public boolean matches(String path) {
 			if (!this.caseSensitive) {
-				path = path.toLowerCase();
+				path = path.toLowerCase(Locale.ROOT);
 			}
 			return path.startsWith(this.subpath) && (path.length() == this.length || path.charAt(this.length) == '/');
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -212,4 +212,14 @@ public class CookieRequestCacheTests {
 		return new String(Base64.getDecoder().decode(encodedCookieValue.getBytes()));
 	}

+	// gh-15905
+	@Test
+	public void illegalCookieValueReturnNull() {
+		CookieRequestCache cookieRequestCache = new CookieRequestCache();
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.setCookies(new Cookie(DEFAULT_COOKIE_NAME, "123^456"));
+		SavedRequest savedRequest = cookieRequestCache.getRequest(request, new MockHttpServletResponse());
+		assertThat(savedRequest).isNull();
+	}
+
 }
@@ -27,12 +27,16 @@ import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 import reactor.core.publisher.Mono;

+import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
 import org.springframework.mock.web.server.MockServerWebExchange;
 import org.springframework.security.web.server.ObservationWebFilterChainDecorator.WebFilterChainObservationContext;
 import org.springframework.security.web.server.ObservationWebFilterChainDecorator.WebFilterChainObservationConvention;
 import org.springframework.security.web.server.ObservationWebFilterChainDecorator.WebFilterObservation;
+import org.springframework.security.web.server.firewall.ServerExchangeRejectedException;
+import org.springframework.security.web.server.firewall.ServerExchangeRejectedHandler;
+import org.springframework.security.web.server.firewall.ServerWebExchangeFirewall;
 import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatcher;
 import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatcher.MatchResult;
 import org.springframework.test.web.reactive.server.WebTestClient;
@@ -48,6 +52,7 @@ import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;

 /**
 * @author Rob Winch
@@ -143,6 +148,77 @@ public class WebFilterChainProxyTests {
 		assertFilterChainObservation(contexts.next(), "before", 1);
 	}

+	@Test
+	void doFilterWhenFirewallThenBadRequest() {
+		List<WebFilter> filters = Arrays.asList(new Http200WebFilter());
+		ServerWebExchangeMatcher notMatch = (exchange) -> MatchResult.notMatch();
+		MatcherSecurityWebFilterChain chain = new MatcherSecurityWebFilterChain(notMatch, filters);
+		WebFilterChainProxy filter = new WebFilterChainProxy(chain);
+		WebTestClient.bindToController(new Object())
+			.webFilter(filter)
+			.build()
+			.method(HttpMethod.valueOf("INVALID"))
+			.exchange()
+			.expectStatus()
+			.isBadRequest();
+	}
+
+	@Test
+	void doFilterWhenCustomFirewallThenInvoked() {
+		List<WebFilter> filters = Arrays.asList(new Http200WebFilter());
+		ServerWebExchangeMatcher notMatch = (exchange) -> MatchResult.notMatch();
+		MatcherSecurityWebFilterChain chain = new MatcherSecurityWebFilterChain(notMatch, filters);
+		WebFilterChainProxy filter = new WebFilterChainProxy(chain);
+		ServerExchangeRejectedHandler handler = mock(ServerExchangeRejectedHandler.class);
+		ServerWebExchangeFirewall firewall = mock(ServerWebExchangeFirewall.class);
+		filter.setFirewall(firewall);
+		filter.setExchangeRejectedHandler(handler);
+		WebTestClient.bindToController(new Object()).webFilter(filter).build().get().exchange();
+		verify(firewall).getFirewalledExchange(any());
+		verifyNoInteractions(handler);
+	}
+
+	@Test
+	void doFilterWhenCustomExchangeRejectedHandlerThenInvoked() {
+		List<WebFilter> filters = Arrays.asList(new Http200WebFilter());
+		ServerWebExchangeMatcher notMatch = (exchange) -> MatchResult.notMatch();
+		MatcherSecurityWebFilterChain chain = new MatcherSecurityWebFilterChain(notMatch, filters);
+		WebFilterChainProxy filter = new WebFilterChainProxy(chain);
+		ServerExchangeRejectedHandler handler = mock(ServerExchangeRejectedHandler.class);
+		ServerWebExchangeFirewall firewall = mock(ServerWebExchangeFirewall.class);
+		given(firewall.getFirewalledExchange(any()))
+			.willReturn(Mono.error(new ServerExchangeRejectedException("Oops")));
+		filter.setFirewall(firewall);
+		filter.setExchangeRejectedHandler(handler);
+		WebTestClient.bindToController(new Object()).webFilter(filter).build().get().exchange();
+		verify(firewall).getFirewalledExchange(any());
+		verify(handler).handle(any(), any());
+	}
+
+	@Test
+	void doFilterWhenDelayedServerExchangeRejectedException() {
+		List<WebFilter> filters = Arrays.asList(new WebFilter() {
+			@Override
+			public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
+				// simulate a delayed error (e.g. reading parameters)
+				return Mono.error(new ServerExchangeRejectedException("Ooops"));
+			}
+		});
+		ServerWebExchangeMatcher match = (exchange) -> MatchResult.match();
+		MatcherSecurityWebFilterChain chain = new MatcherSecurityWebFilterChain(match, filters);
+		WebFilterChainProxy filter = new WebFilterChainProxy(chain);
+		ServerExchangeRejectedHandler handler = mock(ServerExchangeRejectedHandler.class);
+		filter.setExchangeRejectedHandler(handler);
+		// @formatter:off
+		WebTestClient.bindToController(new Object())
+			.webFilter(filter)
+			.build()
+			.get()
+			.exchange();
+		// @formatter:on
+		verify(handler).handle(any(), any());
+	}
+
 	static void assertFilterChainObservation(Observation.Context context, String filterSection, int chainPosition) {
 		assertThat(context).isInstanceOf(WebFilterChainObservationContext.class);
 		WebFilterChainObservationContext filterChainObservationContext = (WebFilterChainObservationContext) context;
@@ -0,0 +1,516 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.web.server.firewall;
+
+import java.net.URI;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.ResponseCookie;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.web.server.MockServerWebExchange;
+import org.springframework.web.server.ServerWebExchange;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+
+/**
+ * Tests for {@link StrictServerWebExchangeFirewall}.
+ *
+ * @author Rob Winch
+ * @since 6.4
+ */
+class StrictServerWebExchangeFirewallTests {
+
+	public String[] unnormalizedPaths = { "http://exploit.example/..", "http://exploit.example/./path/",
+			"http://exploit.example/path/path/.", "http://exploit.example/path/path//.",
+			"http://exploit.example/./path/../path//.", "http://exploit.example/./path",
+			"http://exploit.example/.//path", "http://exploit.example/.", "http://exploit.example//path",
+			"http://exploit.example//path/path", "http://exploit.example//path//path",
+			"http://exploit.example/path//path" };
+
+	private StrictServerWebExchangeFirewall firewall = new StrictServerWebExchangeFirewall();
+
+	private MockServerHttpRequest.BaseBuilder<?> request = get("/");
+
+	@Test
+	void cookieWhenHasNewLineThenThrowsException() {
+		assertThatIllegalArgumentException()
+			.isThrownBy(() -> ResponseCookie.from("test").value("Something\nhere").build());
+	}
+
+	@Test
+	void cookieWhenHasLineFeedThenThrowsException() {
+		assertThatIllegalArgumentException()
+			.isThrownBy(() -> ResponseCookie.from("test").value("Something\rhere").build());
+	}
+
+	@Test
+	void responseHeadersWhenValueHasNewLineThenThrowsException() {
+		this.request = MockServerHttpRequest.get("/");
+		ServerWebExchange exchange = getFirewalledExchange();
+		exchange.getResponse().getHeaders().set("FOO", "new\nline");
+		assertThatIllegalArgumentException().isThrownBy(() -> exchange.getResponse().setComplete().block());
+	}
+
+	@Test
+	void responseHeadersWhenValueHasLineFeedThenThrowsException() {
+		this.request = MockServerHttpRequest.get("/");
+		ServerWebExchange exchange = getFirewalledExchange();
+		exchange.getResponse().getHeaders().set("FOO", "line\rfeed");
+		assertThatIllegalArgumentException().isThrownBy(() -> exchange.getResponse().setComplete().block());
+	}
+
+	@Test
+	void responseHeadersWhenNameHasNewLineThenThrowsException() {
+		this.request = MockServerHttpRequest.get("/");
+		ServerWebExchange exchange = getFirewalledExchange();
+		exchange.getResponse().getHeaders().set("new\nline", "FOO");
+		assertThatIllegalArgumentException().isThrownBy(() -> exchange.getResponse().setComplete().block());
+	}
+
+	@Test
+	void responseHeadersWhenNameHasLineFeedThenThrowsException() {
+		this.request = MockServerHttpRequest.get("/");
+		ServerWebExchange exchange = getFirewalledExchange();
+		exchange.getResponse().getHeaders().set("line\rfeed", "FOO");
+		assertThatIllegalArgumentException().isThrownBy(() -> exchange.getResponse().setComplete().block());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenInvalidMethodThenThrowsServerExchangeRejectedException() {
+		this.request = MockServerHttpRequest.method(HttpMethod.valueOf("INVALID"), "/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	private ServerWebExchange getFirewalledExchange() {
+		MockServerWebExchange exchange = MockServerWebExchange.from(this.request.build());
+		return this.firewall.getFirewalledExchange(exchange).block();
+	}
+
+	private MockServerHttpRequest.BodyBuilder get(String uri) {
+		URI url = URI.create(uri);
+		return MockServerHttpRequest.method(HttpMethod.GET, url);
+	}
+
+	// blocks XST attacks
+	@Test
+	void getFirewalledExchangeWhenTraceMethodThenThrowsServerExchangeRejectedException() {
+		this.request = MockServerHttpRequest.method(HttpMethod.TRACE, "/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	// blocks XST attack if request is forwarded to a Microsoft IIS web server
+	void getFirewalledExchangeWhenTrackMethodThenThrowsServerExchangeRejectedException() {
+		this.request = MockServerHttpRequest.method(HttpMethod.TRACE, "/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	// HTTP methods are case sensitive
+	void getFirewalledExchangeWhenLowercaseGetThenThrowsServerExchangeRejectedException() {
+		this.request = MockServerHttpRequest.method(HttpMethod.valueOf("get"), "/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowedThenNoException() {
+		List<String> allowedMethods = Arrays.asList("DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT");
+		for (String allowedMethod : allowedMethods) {
+			this.request = MockServerHttpRequest.method(HttpMethod.valueOf(allowedMethod), "/");
+			getFirewalledExchange();
+		}
+	}
+
+	@Test
+	void getFirewalledExchangeWhenInvalidMethodAndAnyMethodThenNoException() {
+		this.firewall.setUnsafeAllowAnyHttpMethod(true);
+		this.request = MockServerHttpRequest.method(HttpMethod.valueOf("INVALID"), "/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenURINotNormalizedThenThrowsServerExchangeRejectedException() {
+		for (String path : this.unnormalizedPaths) {
+			this.request = get(path);
+			assertThatExceptionOfType(ServerExchangeRejectedException.class)
+				.describedAs("The path '" + path + "' is not normalized")
+				.isThrownBy(() -> getFirewalledExchange());
+		}
+	}
+
+	@Test
+	void getFirewalledExchangeWhenSemicolonInRequestUriThenThrowsServerExchangeRejectedException() {
+		this.request = get("/path;/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenEncodedSemicolonInRequestUriThenThrowsServerExchangeRejectedException() {
+		this.request = get("/path%3B/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenLowercaseEncodedSemicolonInRequestUriThenThrowsServerExchangeRejectedException() {
+		this.request = MockServerHttpRequest.method(HttpMethod.GET, URI.create("/path%3b/"));
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenSemicolonInRequestUriAndAllowSemicolonThenNoException() {
+		this.firewall.setAllowSemicolon(true);
+		this.request = get("/path;/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenEncodedSemicolonInRequestUriAndAllowSemicolonThenNoException() {
+		this.firewall.setAllowSemicolon(true);
+		this.request = get("/path%3B/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenLowercaseEncodedSemicolonInRequestUriAndAllowSemicolonThenNoException() {
+		this.firewall.setAllowSemicolon(true);
+		this.request = get("/path%3b/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenLowercaseEncodedPeriodInThenThrowsServerExchangeRejectedException() {
+		this.request = get("/%2e/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsLowerboundAsciiThenNoException() {
+		this.request = get("/%20");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsUpperboundAsciiThenNoException() {
+		this.request = get("/~");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenJapaneseCharacterThenNoException() {
+		// FIXME: .method(HttpMethod.GET to .get and similar methods
+		this.request = get("/\u3042");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsEncodedNullThenException() {
+		this.request = get("/something%00/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsLowercaseEncodedLineFeedThenException() {
+		this.request = get("/something%0a/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsUppercaseEncodedLineFeedThenException() {
+		this.request = get("/something%0A/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsLowercaseEncodedCarriageReturnThenException() {
+		this.request = get("/something%0d/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsUppercaseEncodedCarriageReturnThenException() {
+		this.request = get("/something%0D/");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsLowercaseEncodedLineFeedAndAllowedThenNoException() {
+		this.firewall.setAllowUrlEncodedLineFeed(true);
+		this.request = get("/something%0a/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsUppercaseEncodedLineFeedAndAllowedThenNoException() {
+		this.firewall.setAllowUrlEncodedLineFeed(true);
+		this.request = get("/something%0A/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsLowercaseEncodedCarriageReturnAndAllowedThenNoException() {
+		this.firewall.setAllowUrlEncodedCarriageReturn(true);
+		this.request = get("/something%0d/");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenContainsUppercaseEncodedCarriageReturnAndAllowedThenNoException() {
+		this.firewall.setAllowUrlEncodedCarriageReturn(true);
+		this.request = get("/something%0D/");
+		getFirewalledExchange();
+	}
+
+	/**
+	 * On WebSphere 8.5 a URL like /context-root/a/b;%2f1/c can bypass a rule on /a/b/c
+	 * because the pathInfo is /a/b;/1/c which ends up being /a/b/1/c while Spring MVC
+	 * will strip the ; content from requestURI before the path is URL decoded.
+	 */
+	@Test
+	void getFirewalledExchangeWhenLowercaseEncodedPathThenException() {
+		this.request = get("/context-root/a/b;%2f1/c");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenUppercaseEncodedPathThenException() {
+		this.request = get("/context-root/a/b;%2F1/c");
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowUrlEncodedSlashAndLowercaseEncodedPathThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.firewall.setAllowSemicolon(true);
+		this.request = get("/context-root/a/b;%2f1/c");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowUrlEncodedSlashAndUppercaseEncodedPathThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.firewall.setAllowSemicolon(true);
+		this.request = get("/context-root/a/b;%2F1/c");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowUrlLowerCaseEncodedDoubleSlashThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.firewall.setAllowUrlEncodedDoubleSlash(true);
+		this.request = get("/context-root/a/b%2f%2fc");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowUrlUpperCaseEncodedDoubleSlashThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.firewall.setAllowUrlEncodedDoubleSlash(true);
+		this.request = get("/context-root/a/b%2F%2Fc");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowUrlLowerCaseAndUpperCaseEncodedDoubleSlashThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.firewall.setAllowUrlEncodedDoubleSlash(true);
+		this.request = get("/context-root/a/b%2f%2Fc");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenAllowUrlUpperCaseAndLowerCaseEncodedDoubleSlashThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.firewall.setAllowUrlEncodedDoubleSlash(true);
+		this.request = get("/context-root/a/b%2F%2fc");
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenRemoveFromUpperCaseEncodedUrlBlocklistThenNoException() {
+		this.firewall.setAllowUrlEncodedSlash(true);
+		this.request = get("/context-root/a/b%2Fc");
+		this.firewall.getEncodedUrlBlocklist().removeAll(Arrays.asList("%2F%2F"));
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenRemoveFromDecodedUrlBlocklistThenNoException() {
+		this.request = get("/a/b%2F%2Fc");
+		this.firewall.getDecodedUrlBlocklist().removeAll(Arrays.asList("//"));
+		this.firewall.getEncodedUrlBlocklist().removeAll(Arrays.asList("%2F%2F"));
+		this.firewall.getEncodedUrlBlocklist().removeAll(Arrays.asList("%2F"));
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenTrustedDomainThenNoException() {
+		this.request.header("Host", "example.org");
+		this.firewall.setAllowedHostnames((hostname) -> hostname.equals("example.org"));
+		getFirewalledExchange();
+	}
+
+	@Test
+	void getFirewalledExchangeWhenUntrustedDomainThenException() {
+		this.request = get("https://example.org");
+		this.firewall.setAllowedHostnames((hostname) -> hostname.equals("myexample.org"));
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> getFirewalledExchange());
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderWhenNotAllowedHeaderNameThenException() {
+		this.firewall.setAllowedHeaderNames((name) -> !name.equals("bad name"));
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("bad name"));
+	}
+
+	@Test
+	void getFirewalledExchangeWhenHeaderNameNotAllowedWithAugmentedHeaderNamesThenException() {
+		this.firewall.setAllowedHeaderNames(
+				StrictServerWebExchangeFirewall.ALLOWED_HEADER_NAMES.and((name) -> !name.equals("bad name")));
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.getFirst("bad name"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderWhenNotAllowedHeaderValueThenException() {
+		this.request.header("good name", "bad value");
+		this.firewall.setAllowedHeaderValues((value) -> !value.equals("bad value"));
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("good name"));
+	}
+
+	@Test
+	void getFirewalledExchangeWhenHeaderValueNotAllowedWithAugmentedHeaderValuesThenException() {
+		this.request.header("good name", "bad value");
+		this.firewall.setAllowedHeaderValues(
+				StrictServerWebExchangeFirewall.ALLOWED_HEADER_VALUES.and((value) -> !value.equals("bad value")));
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("good name"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetDateHeaderWhenControlCharacterInHeaderNameThenException() {
+		this.request.header("Bad\0Name", "some value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("Bad\0Name"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderWhenUndefinedCharacterInHeaderNameThenException() {
+		this.request.header("Bad\uFFFEName", "some value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("Bad\uFFFEName"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeadersWhenControlCharacterInHeaderNameThenException() {
+		this.request.header("Bad\0Name", "some value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("Bad\0Name"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderNamesWhenControlCharacterInHeaderNameThenException() {
+		this.request.header("Bad\0Name", "some value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class)
+			.isThrownBy(() -> headers.keySet().iterator().next());
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderWhenControlCharacterInHeaderValueThenException() {
+		this.request.header("Something", "bad\0value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("Something"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderWhenHorizontalTabInHeaderValueThenNoException() {
+		this.request.header("Something", "tab\tvalue");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThat(headers.getFirst("Something")).isEqualTo("tab\tvalue");
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeaderWhenUndefinedCharacterInHeaderValueThenException() {
+		this.request.header("Something", "bad\uFFFEvalue");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class)
+			.isThrownBy(() -> headers.getFirst("Something"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetHeadersWhenControlCharacterInHeaderValueThenException() {
+		this.request.header("Something", "bad\0value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> headers.get("Something"));
+	}
+
+	@Test
+	void getFirewalledExchangeGetParameterWhenControlCharacterInParameterNameThenException() {
+		this.request.queryParam("Bad\0Name", "some value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		ServerHttpRequest request = exchange.getRequest();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(request::getQueryParams);
+	}
+
+	@Test
+	void getFirewalledExchangeGetParameterValuesWhenNotAllowedInParameterValueThenException() {
+		this.firewall.setAllowedParameterValues((value) -> !value.equals("bad value"));
+		this.request.queryParam("Something", "bad value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		ServerHttpRequest request = exchange.getRequest();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> request.getQueryParams());
+	}
+
+	@Test
+	void getFirewalledExchangeGetParameterValuesWhenNotAllowedInParameterNameThenException() {
+		this.firewall.setAllowedParameterNames((value) -> !value.equals("bad name"));
+		this.request.queryParam("bad name", "good value");
+		ServerWebExchange exchange = getFirewalledExchange();
+		ServerHttpRequest request = exchange.getRequest();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class).isThrownBy(() -> request.getQueryParams());
+	}
+
+	// gh-9598
+	@Test
+	void getFirewalledExchangeGetHeaderWhenNameIsNullThenNull() {
+		ServerWebExchange exchange = getFirewalledExchange();
+		assertThat(exchange.getRequest().getHeaders().get(null)).isNull();
+	}
+
+}