Release 6.3.5

Bumps [io.micrometer:micrometer-observation](https://github.com/micrometer-metrics/micrometer) from 1.12.12 to 1.12.13.
- [Release notes](https://github.com/micrometer-metrics/micrometer/releases)
- [Commits](https://github.com/micrometer-metrics/micrometer/compare/v1.12.12...v1.12.13)

---
updated-dependencies:
- dependency-name: io.micrometer:micrometer-observation
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

cas/src/main/java/org/springframework/security/cas/userdetails/GrantedAuthorityFromAssertionAttributesUserDetailsService.java

@@ -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());
 	}
 
 	/**

config/src/main/java/org/springframework/security/config/annotation/web/configurers/AuthorizeHttpRequestsConfigurer.java

@@ -174,7 +174,8 @@ 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;
 			}

config/src/main/java/org/springframework/security/config/annotation/web/reactive/WebFluxSecurityConfiguration.java

@@ -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;
 	}
 

config/src/main/java/org/springframework/security/config/http/HttpConfigurationBuilder.java

@@ -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() {

config/src/main/java/org/springframework/security/config/web/server/OidcBackChannelLogoutReactiveAuthenticationManager.java

@@ -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.
@@ -16,6 +16,10 @@
 
 package org.springframework.security.config.web.server;
 
+import com.nimbusds.jose.JOSEObjectType;
+import com.nimbusds.jose.proc.DefaultJOSEObjectTypeVerifier;
+import com.nimbusds.jose.proc.JOSEObjectTypeVerifier;
+import com.nimbusds.jose.proc.JWKSecurityContext;
 import reactor.core.publisher.Mono;
 
 import org.springframework.security.authentication.AuthenticationProvider;
@@ -23,19 +27,22 @@ import org.springframework.security.authentication.AuthenticationServiceExceptio
 import org.springframework.security.authentication.ReactiveAuthenticationManager;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.AuthenticationException;
-import org.springframework.security.oauth2.client.oidc.authentication.ReactiveOidcIdTokenDecoderFactory;
+import org.springframework.security.oauth2.client.oidc.authentication.OidcIdTokenDecoderFactory;
 import org.springframework.security.oauth2.client.oidc.authentication.logout.OidcLogoutToken;
 import org.springframework.security.oauth2.client.registration.ClientRegistration;
 import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
 import org.springframework.security.oauth2.core.OAuth2Error;
 import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
+import org.springframework.security.oauth2.core.converter.ClaimTypeConverter;
 import org.springframework.security.oauth2.jwt.BadJwtException;
 import org.springframework.security.oauth2.jwt.Jwt;
 import org.springframework.security.oauth2.jwt.JwtDecoder;
 import org.springframework.security.oauth2.jwt.JwtDecoderFactory;
+import org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder;
 import org.springframework.security.oauth2.jwt.ReactiveJwtDecoder;
 import org.springframework.security.oauth2.jwt.ReactiveJwtDecoderFactory;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 /**
  * An {@link AuthenticationProvider} that authenticates an OIDC Logout Token; namely
@@ -61,9 +68,27 @@ final class OidcBackChannelLogoutReactiveAuthenticationManager implements Reacti
 	 * Construct an {@link OidcBackChannelLogoutReactiveAuthenticationManager}
 	 */
 	OidcBackChannelLogoutReactiveAuthenticationManager() {
-		ReactiveOidcIdTokenDecoderFactory logoutTokenDecoderFactory = new ReactiveOidcIdTokenDecoderFactory();
-		logoutTokenDecoderFactory.setJwtValidatorFactory(new DefaultOidcLogoutTokenValidatorFactory());
-		this.logoutTokenDecoderFactory = logoutTokenDecoderFactory;
+		DefaultOidcLogoutTokenValidatorFactory jwtValidator = new DefaultOidcLogoutTokenValidatorFactory();
+		this.logoutTokenDecoderFactory = (clientRegistration) -> {
+			String jwkSetUri = clientRegistration.getProviderDetails().getJwkSetUri();
+			if (!StringUtils.hasText(jwkSetUri)) {
+				OAuth2Error oauth2Error = new OAuth2Error("missing_signature_verifier",
+						"Failed to find a Signature Verifier for Client Registration: '"
+								+ clientRegistration.getRegistrationId()
+								+ "'. Check to ensure you have configured the JwkSet URI.",
+						null);
+				throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString());
+			}
+			JOSEObjectTypeVerifier<JWKSecurityContext> typeVerifier = new DefaultJOSEObjectTypeVerifier<>(null,
+					JOSEObjectType.JWT, new JOSEObjectType("logout+jwt"));
+			NimbusReactiveJwtDecoder decoder = NimbusReactiveJwtDecoder.withJwkSetUri(jwkSetUri)
+				.jwtProcessorCustomizer((processor) -> processor.setJWSTypeVerifier(typeVerifier))
+				.build();
+			decoder.setJwtValidator(jwtValidator.apply(clientRegistration));
+			decoder.setClaimSetConverter(
+					new ClaimTypeConverter(OidcIdTokenDecoderFactory.createDefaultClaimTypeConverters()));
+			return decoder;
+		};
 	}
 
 	/**

config/src/test/java/org/springframework/security/config/annotation/web/configurers/AuthorizeHttpRequestsConfigurerTests.java

@@ -155,6 +155,7 @@ 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));
 	}
 

config/src/test/java/org/springframework/security/config/annotation/web/reactive/WebFluxSecurityConfigurationTests.java

@@ -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 {
 

config/src/test/java/org/springframework/security/config/web/server/OidcLogoutSpecTests.java

@@ -74,6 +74,8 @@ import org.springframework.security.oauth2.client.registration.TestClientRegistr
 import org.springframework.security.oauth2.core.oidc.OidcIdToken;
 import org.springframework.security.oauth2.core.oidc.TestOidcIdTokens;
 import org.springframework.security.oauth2.core.oidc.user.OidcUser;
+import org.springframework.security.oauth2.jose.jws.SignatureAlgorithm;
+import org.springframework.security.oauth2.jwt.JwsHeader;
 import org.springframework.security.oauth2.jwt.JwtClaimsSet;
 import org.springframework.security.oauth2.jwt.JwtEncoder;
 import org.springframework.security.oauth2.jwt.JwtEncoderParameters;
@@ -694,8 +696,9 @@ public class OidcLogoutSpecTests {
 		String logoutToken(@AuthenticationPrincipal OidcUser user) {
 			OidcLogoutToken token = TestOidcLogoutTokens.withUser(user)
 					.audience(List.of(this.registration.getClientId())).build();
-			JwtEncoderParameters parameters = JwtEncoderParameters
-					.from(JwtClaimsSet.builder().claims((claims) -> claims.putAll(token.getClaims())).build());
+			JwsHeader header = JwsHeader.with(SignatureAlgorithm.RS256).type("logout+jwt").build();
+			JwtClaimsSet claims = JwtClaimsSet.builder().claims((c) -> c.putAll(token.getClaims())).build();
+			JwtEncoderParameters parameters = JwtEncoderParameters.from(header, claims);
 			return this.encoder.encode(parameters).getTokenValue();
 		}
 
@@ -704,8 +707,9 @@ public class OidcLogoutSpecTests {
 			OidcLogoutToken token = TestOidcLogoutTokens.withUser(user)
 					.audience(List.of(this.registration.getClientId()))
 					.claims((claims) -> claims.remove(LogoutTokenClaimNames.SID)).build();
-			JwtEncoderParameters parameters = JwtEncoderParameters
-					.from(JwtClaimsSet.builder().claims((claims) -> claims.putAll(token.getClaims())).build());
+			JwsHeader header = JwsHeader.with(SignatureAlgorithm.RS256).type("JWT").build();
+			JwtClaimsSet claims = JwtClaimsSet.builder().claims((c) -> c.putAll(token.getClaims())).build();
+			JwtEncoderParameters parameters = JwtEncoderParameters.from(header, claims);
 			return this.encoder.encode(parameters).getTokenValue();
 		}
 	}

core/src/main/java/org/springframework/security/authentication/AuthenticationObservationConvention.java

@@ -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";
 	}

core/src/main/java/org/springframework/security/core/authority/mapping/SimpleAttributes2GrantedAuthoritiesMapper.java

@@ -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);

core/src/main/java/org/springframework/security/core/authority/mapping/SimpleAuthorityMapper.java

@@ -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;

core/src/main/java/org/springframework/security/core/userdetails/MapReactiveUserDetailsService.java

@@ -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);
 	}
 
 }

core/src/main/java/org/springframework/security/core/userdetails/memory/UserAttributeEditor.java

@@ -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 {

core/src/main/java/org/springframework/security/provisioning/InMemoryUserDetailsManager.java

@@ -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);
 		}

crypto/src/main/java/org/springframework/security/crypto/password/LdapShaPasswordEncoder.java

@@ -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;
 

docs/antora-playbook.yml

@@ -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:

docs/modules/ROOT/pages/reactive/exploits/firewall.adoc

@@ -200,3 +200,35 @@ firewall.setAllowedHeaderValues {
 }
 ----
 ======
+
+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.

docs/modules/ROOT/pages/servlet/authentication/logout.adoc

@@ -315,7 +315,7 @@ While using `logoutSuccessUrl` will suffice for most cases, you may need to do s
 For example, instead of redirecting, you may want to only return a status code.
 In this case, you can provide a success handler instance, like so:
 
-.Using Clear-Site-Data to Clear Cookies
+.Using HttpStatusReturningLogoutSuccessHandler to return a status code
 [tabs]
 ======
 Java::

docs/package.json

@@ -2,7 +2,7 @@
   "dependencies": {
     "antora": "3.2.0-alpha.6",
     "@antora/atlas-extension": "1.0.0-alpha.2",
-    "@antora/collector-extension": "1.0.0-beta.3",
+    "@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.14"

etc/checkstyle/checkstyle-suppressions.xml

@@ -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>

etc/checkstyle/checkstyle.xml

@@ -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>

gradle.properties

@@ -1,5 +1,5 @@
 springBootVersion=3.1.1
-version=6.3.4
+version=6.3.5
 samplesBranch=6.3.x
 org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.parallel=true

gradle/libs.versions.toml

@@ -13,11 +13,11 @@ org-jetbrains-kotlin = "1.9.25"
 org-jetbrains-kotlinx = "1.8.1"
 org-mockito = "5.11.0"
 org-opensaml = "4.3.2"
-org-springframework = "6.1.14"
+org-springframework = "6.1.15"
 
 [libraries]
-ch-qos-logback-logback-classic = "ch.qos.logback:logback-classic:1.5.11"
-com-fasterxml-jackson-jackson-bom = "com.fasterxml.jackson:jackson-bom:2.17.2"
+ch-qos-logback-logback-classic = "ch.qos.logback:logback-classic:1.5.12"
+com-fasterxml-jackson-jackson-bom = "com.fasterxml.jackson:jackson-bom:2.17.3"
 com-google-inject-guice = "com.google.inject:guice:3.0"
 com-netflix-nebula-nebula-project-plugin = "com.netflix.nebula:nebula-project-plugin:8.2.0"
 com-nimbusds-nimbus-jose-jwt = "com.nimbusds:nimbus-jose-jwt:9.37.3"
@@ -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:1.12.11"
+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:2023.0.11"
+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" }
@@ -68,7 +68,7 @@ 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:6.4.10.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" }
@@ -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:2024.0.5"
-org-springframework-ldap-spring-ldap-core = "org.springframework.ldap:spring-ldap-core:3.2.7"
+org-springframework-data-spring-data-bom = "org.springframework.data:spring-data-bom:2024.0.6"
+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"
 

ldap/src/main/java/org/springframework/security/ldap/LdapEncoder.java

@@ -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;
 	}
 

ldap/src/main/java/org/springframework/security/ldap/authentication/LdapEncoder.java

@@ -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;
 	}
 

ldap/src/main/java/org/springframework/security/ldap/authentication/ad/ActiveDirectoryLdapAuthenticationProvider.java

@@ -20,6 +20,7 @@ import java.io.Serializable;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Hashtable;
+import java.util.Locale;
 import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -142,9 +143,9 @@ 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;
 	}
 
 	/**
@@ -153,7 +154,7 @@ 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;
 	}
@@ -336,7 +337,7 @@ 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;

ldap/src/main/java/org/springframework/security/ldap/userdetails/DefaultLdapAuthoritiesPopulator.java

@@ -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);
 		};

ldap/src/main/java/org/springframework/security/ldap/userdetails/LdapUserDetailsManager.java

@@ -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;
@@ -287,7 +288,7 @@ public class LdapUserDetailsManager implements UserDetailsManager {
 	 */
 	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;
 	}
 

ldap/src/main/java/org/springframework/security/ldap/userdetails/LdapUserDetailsMapper.java

@@ -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);
 		}

ldap/src/main/java/org/springframework/security/ldap/userdetails/NestedLdapAuthoritiesPopulator.java

@@ -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.

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/reactive/function/client/ServerOAuth2AuthorizedClientExchangeFilterFunction.java

@@ -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)

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/reactive/function/client/ServletOAuth2AuthorizedClientExchangeFilterFunction.java

@@ -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)

oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/DefaultBearerTokenResolver.java

@@ -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;

oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/server/authentication/ServerBearerTokenAuthenticationConverter.java

@@ -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;

oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/web/DefaultBearerTokenResolverTests.java

@@ -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);
+			});
+	}
+
 }

oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/web/server/authentication/ServerBearerTokenAuthenticationConverterTests.java

@@ -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
 	}

taglibs/src/main/java/org/springframework/security/taglibs/authz/AbstractAuthorizeTag.java

@@ -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() {

web/src/main/java/org/springframework/security/web/PortResolverImpl.java

@@ -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;
 	}

web/src/main/java/org/springframework/security/web/authentication/DelegatingAuthenticationConverter.java

@@ -16,7 +16,6 @@
 
 package org.springframework.security.web.authentication;
 
-import java.util.ArrayList;
 import java.util.List;
 
 import jakarta.servlet.http.HttpServletRequest;
@@ -38,7 +37,7 @@ public final class DelegatingAuthenticationConverter implements AuthenticationCo
 
 	public DelegatingAuthenticationConverter(List<AuthenticationConverter> delegates) {
 		Assert.notEmpty(delegates, "delegates cannot be null");
-		this.delegates = new ArrayList<>(delegates);
+		this.delegates = List.copyOf(delegates);
 	}
 
 	public DelegatingAuthenticationConverter(AuthenticationConverter... delegates) {

web/src/main/java/org/springframework/security/web/authentication/password/HaveIBeenPwnedRestApiPasswordChecker.java

@@ -21,6 +21,7 @@ import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -63,7 +64,7 @@ public final class HaveIBeenPwnedRestApiPasswordChecker implements CompromisedPa
 	@NonNull
 	public CompromisedPasswordDecision check(String password) {
 		byte[] hash = this.sha1Digest.digest(password.getBytes(StandardCharsets.UTF_8));
-		String encoded = new String(Hex.encode(hash)).toUpperCase();
+		String encoded = new String(Hex.encode(hash)).toUpperCase(Locale.ROOT);
 		String prefix = encoded.substring(0, PREFIX_LENGTH);
 		String suffix = encoded.substring(PREFIX_LENGTH);
 

web/src/main/java/org/springframework/security/web/authentication/password/HaveIBeenPwnedRestApiReactivePasswordChecker.java

@@ -19,6 +19,7 @@ package org.springframework.security.web.authentication.password;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.Locale;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -67,8 +68,8 @@ public class HaveIBeenPwnedRestApiReactivePasswordChecker implements ReactiveCom
 	}
 
 	private Mono<Boolean> findLeakedPassword(String encodedPassword) {
-		String prefix = encodedPassword.substring(0, PREFIX_LENGTH).toUpperCase();
-		String suffix = encodedPassword.substring(PREFIX_LENGTH).toUpperCase();
+		String prefix = encodedPassword.substring(0, PREFIX_LENGTH).toUpperCase(Locale.ROOT);
+		String suffix = encodedPassword.substring(PREFIX_LENGTH).toUpperCase(Locale.ROOT);
 		return getLeakedPasswordsForPrefix(prefix).any((leakedPw) -> leakedPw.startsWith(suffix));
 	}
 

web/src/main/java/org/springframework/security/web/savedrequest/CookieRequestCache.java

@@ -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) {

web/src/main/java/org/springframework/security/web/util/UrlUtils.java

@@ -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

web/src/main/java/org/springframework/security/web/util/matcher/AntPathRequestMatcher.java

@@ -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) == '/');
 		}

web/src/main/java/org/springframework/security/web/util/matcher/IpAddressMatcher.java

@@ -18,6 +18,7 @@ package org.springframework.security.web.util.matcher;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.util.Objects;
 import java.util.regex.Pattern;
 
 import jakarta.servlet.http.HttpServletRequest;
@@ -33,16 +34,17 @@ import org.springframework.util.StringUtils;
  * IPv4 address will never match a request which returns an IPv6 address, and vice-versa.
  *
  * @author Luke Taylor
+ * @author Steve Riesenberg
  * @since 3.0.2
  */
 public final class IpAddressMatcher implements RequestMatcher {
 
 	private static Pattern IPV4 = Pattern.compile("\\d{0,3}.\\d{0,3}.\\d{0,3}.\\d{0,3}(/\\d{0,3})?");
 
-	private final int nMaskBits;
-
 	private final InetAddress requiredAddress;
 
+	private final int nMaskBits;
+
 	/**
 	 * Takes a specific IP address or a range specified using the IP/Netmask (e.g.
 	 * 192.168.1.0/24 or 202.24.0.0/14).
@@ -50,19 +52,24 @@ public final class IpAddressMatcher implements RequestMatcher {
 	 * come.
 	 */
 	public IpAddressMatcher(String ipAddress) {
+		Assert.hasText(ipAddress, "ipAddress cannot be empty");
 		assertNotHostName(ipAddress);
+
+		String requiredAddress;
+		int nMaskBits;
 		if (ipAddress.indexOf('/') > 0) {
-			String[] addressAndMask = StringUtils.split(ipAddress, "/");
-			ipAddress = addressAndMask[0];
-			this.nMaskBits = Integer.parseInt(addressAndMask[1]);
+			String[] parts = Objects.requireNonNull(StringUtils.split(ipAddress, "/"));
+			requiredAddress = parts[0];
+			nMaskBits = Integer.parseInt(parts[1]);
 		}
 		else {
-			this.nMaskBits = -1;
+			requiredAddress = ipAddress;
+			nMaskBits = -1;
 		}
-		this.requiredAddress = parseAddress(ipAddress);
-		String finalIpAddress = ipAddress;
+		this.requiredAddress = parseAddress(requiredAddress);
+		this.nMaskBits = nMaskBits;
 		Assert.isTrue(this.requiredAddress.getAddress().length * 8 >= this.nMaskBits, () -> String
-			.format("IP address %s is too short for bitmask of length %d", finalIpAddress, this.nMaskBits));
+			.format("IP address %s is too short for bitmask of length %d", requiredAddress, this.nMaskBits));
 	}
 
 	@Override
@@ -70,9 +77,14 @@ public final class IpAddressMatcher implements RequestMatcher {
 		return matches(request.getRemoteAddr());
 	}
 
-	public boolean matches(String address) {
-		assertNotHostName(address);
-		InetAddress remoteAddress = parseAddress(address);
+	public boolean matches(String ipAddress) {
+		// Do not match null or blank address
+		if (!StringUtils.hasText(ipAddress)) {
+			return false;
+		}
+
+		assertNotHostName(ipAddress);
+		InetAddress remoteAddress = parseAddress(ipAddress);
 		if (!this.requiredAddress.getClass().equals(remoteAddress.getClass())) {
 			return false;
 		}
@@ -82,26 +94,31 @@ public final class IpAddressMatcher implements RequestMatcher {
 		byte[] remAddr = remoteAddress.getAddress();
 		byte[] reqAddr = this.requiredAddress.getAddress();
 		int nMaskFullBytes = this.nMaskBits / 8;
-		byte finalByte = (byte) (0xFF00 >> (this.nMaskBits & 0x07));
 		for (int i = 0; i < nMaskFullBytes; i++) {
 			if (remAddr[i] != reqAddr[i]) {
 				return false;
 			}
 		}
+		byte finalByte = (byte) (0xFF00 >> (this.nMaskBits & 0x07));
 		if (finalByte != 0) {
 			return (remAddr[nMaskFullBytes] & finalByte) == (reqAddr[nMaskFullBytes] & finalByte);
 		}
 		return true;
 	}
 
-	private void assertNotHostName(String ipAddress) {
-		boolean isIpv4 = IPV4.matcher(ipAddress).matches();
-		if (isIpv4) {
-			return;
-		}
-		String error = "ipAddress " + ipAddress + " doesn't look like an IP Address. Is it a host name?";
-		Assert.isTrue(ipAddress.charAt(0) == '[' || ipAddress.charAt(0) == ':'
-				|| (Character.digit(ipAddress.charAt(0), 16) != -1 && ipAddress.contains(":")), error);
+	private static void assertNotHostName(String ipAddress) {
+		Assert.isTrue(isIpAddress(ipAddress),
+				() -> String.format("ipAddress %s doesn't look like an IP Address. Is it a host name?", ipAddress));
+	}
+
+	private static boolean isIpAddress(String ipAddress) {
+		// @formatter:off
+		return IPV4.matcher(ipAddress).matches()
+			|| ipAddress.charAt(0) == '['
+			|| ipAddress.charAt(0) == ':'
+			|| Character.digit(ipAddress.charAt(0), 16) != -1
+			&& ipAddress.indexOf(':') > 0;
+		// @formatter:on
 	}
 
 	private InetAddress parseAddress(String address) {

web/src/test/java/org/springframework/security/web/savedrequest/CookieRequestCacheTests.java

@@ -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();
+	}
+
 }

web/src/test/java/org/springframework/security/web/util/matcher/IpAddressMatcherTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 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.
@@ -126,4 +126,31 @@ public class IpAddressMatcherTests {
 			.withMessage("ipAddress 123.156.7.18.org doesn't look like an IP Address. Is it a host name?");
 	}
 
+	// gh-15527
+	@Test
+	public void matchesWhenIpAddressIsLoopbackAndAddressIsNullThenFalse() {
+		IpAddressMatcher ipAddressMatcher = new IpAddressMatcher("127.0.0.1");
+		assertThat(ipAddressMatcher.matches((String) null)).isFalse();
+	}
+
+	// gh-15527
+	@Test
+	public void matchesWhenAddressIsNullThenFalse() {
+		assertThat(this.v4matcher.matches((String) null)).isFalse();
+	}
+
+	// gh-15527
+	@Test
+	public void constructorWhenRequiredAddressIsNullThenThrowsIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new IpAddressMatcher(null))
+			.withMessage("ipAddress cannot be empty");
+	}
+
+	// gh-15527
+	@Test
+	public void constructorWhenRequiredAddressIsEmptyThenThrowsIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new IpAddressMatcher(""))
+			.withMessage("ipAddress cannot be empty");
+	}
+
 }