Release 6.3.6

Bump org.springframework.data:spring-data-bom from 2024.0.6 to 2024.0.7
Bumps [org.springframework.data:spring-data-bom](https://github.com/spring-projects/spring-data-bom) from 2024.0.6 to 2024.0.7. - [Release notes](https://github.com/spring-projects/spring-data-bom/releases) - [Commits](https://github.com/spring-projects/spring-data-bom/compare/2024.0.6...2024.0.7) --- updated-dependencies: - dependency-name: org.springframework.data:spring-data-bom dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com>
2026-07-15 23:55:09 +00:00 · 2024-12-16 15:23:29 +00:00 · 2024-12-15 19:26:03 -08:00 · 2024-12-12 13:24:18 -08:00 · 2024-12-12 13:11:47 -08:00 · 2024-12-11 18:00:31 -06:00
78 changed files with 1046 additions and 271 deletions
@@ -9,7 +9,7 @@ on:
  workflow_dispatch: # Manual trigger

 env:
-  DEVELOCITY_ACCESS_KEY: ${{ secrets.GRADLE_ENTERPRISE_SECRET_ACCESS_KEY }}
+  DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}

 permissions:
  contents: read
@@ -2,9 +2,6 @@ name: PR Build

 on: pull_request

-env:
-  DEVELOCITY_ACCESS_KEY: ${{ secrets.GRADLE_ENTERPRISE_SECRET_ACCESS_KEY }}
-
 permissions:
  contents: read

@@ -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());
 	}

 	/**
@@ -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.
@@ -16,8 +16,7 @@

 package org.springframework.security.config.annotation.authentication.configuration;

-import java.util.ArrayList;
-import java.util.List;
+import java.util.Arrays;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -63,62 +62,24 @@ class InitializeAuthenticationProviderBeanManagerConfigurer extends GlobalAuthen
 			if (auth.isConfigured()) {
 				return;
 			}
-			List<BeanWithName<AuthenticationProvider>> authenticationProviders = getBeansWithName(
-					AuthenticationProvider.class);
-			if (authenticationProviders.isEmpty()) {
+			String[] beanNames = InitializeAuthenticationProviderBeanManagerConfigurer.this.context
+				.getBeanNamesForType(AuthenticationProvider.class);
+			if (beanNames.length == 0) {
 				return;
 			}
-			else if (authenticationProviders.size() > 1) {
-				List<String> beanNames = authenticationProviders.stream().map(BeanWithName::getName).toList();
+			else if (beanNames.length > 1) {
 				this.logger.info(LogMessage.format("Found %s AuthenticationProvider beans, with names %s. "
 						+ "Global Authentication Manager will not be configured with AuthenticationProviders. "
 						+ "Consider publishing a single AuthenticationProvider bean, or wiring your Providers directly "
-						+ "using the DSL.", authenticationProviders.size(), beanNames));
+						+ "using the DSL.", beanNames.length, Arrays.toString(beanNames)));
 				return;
 			}
-			AuthenticationProvider authenticationProvider = authenticationProviders.get(0).getBean();
-			String authenticationProviderBeanName = authenticationProviders.get(0).getName();
-
+			AuthenticationProvider authenticationProvider = InitializeAuthenticationProviderBeanManagerConfigurer.this.context
+				.getBean(beanNames[0], AuthenticationProvider.class);
 			auth.authenticationProvider(authenticationProvider);
 			this.logger.info(LogMessage.format(
 					"Global AuthenticationManager configured with AuthenticationProvider bean with name %s",
-					authenticationProviderBeanName));
-		}
-
-		/**
-		 * @return a list of beans of the requested class, along with their names. If
-		 * there are no registered beans of that type, the list is empty.
-		 */
-		private <T> List<BeanWithName<T>> getBeansWithName(Class<T> type) {
-			List<BeanWithName<T>> beanWithNames = new ArrayList<>();
-			String[] beanNames = InitializeAuthenticationProviderBeanManagerConfigurer.this.context
-				.getBeanNamesForType(type);
-			for (String beanName : beanNames) {
-				T bean = InitializeAuthenticationProviderBeanManagerConfigurer.this.context.getBean(beanName, type);
-				beanWithNames.add(new BeanWithName<T>(bean, beanName));
-			}
-			return beanWithNames;
-		}
-
-		static class BeanWithName<T> {
-
-			private final T bean;
-
-			private final String name;
-
-			BeanWithName(T bean, String name) {
-				this.bean = bean;
-				this.name = name;
-			}
-
-			T getBean() {
-				return this.bean;
-			}
-
-			String getName() {
-				return this.name;
-			}
-
+					beanNames[0]));
 		}

 	}
@@ -16,8 +16,7 @@

 package org.springframework.security.config.annotation.authentication.configuration;

-import java.util.ArrayList;
-import java.util.List;
+import java.util.Arrays;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -66,9 +65,10 @@ class InitializeUserDetailsBeanManagerConfigurer extends GlobalAuthenticationCon

 		@Override
 		public void configure(AuthenticationManagerBuilder auth) throws Exception {
-			List<BeanWithName<UserDetailsService>> userDetailsServices = getBeansWithName(UserDetailsService.class);
+			String[] beanNames = InitializeUserDetailsBeanManagerConfigurer.this.context
+				.getBeanNamesForType(UserDetailsService.class);
 			if (auth.isConfigured()) {
-				if (!userDetailsServices.isEmpty()) {
+				if (beanNames.length > 0) {
 					this.logger.warn("Global AuthenticationManager configured with an AuthenticationProvider bean. "
 							+ "UserDetailsService beans will not be used for username/password login. "
 							+ "Consider removing the AuthenticationProvider bean. "
@@ -78,19 +78,18 @@ class InitializeUserDetailsBeanManagerConfigurer extends GlobalAuthenticationCon
 				return;
 			}

-			if (userDetailsServices.isEmpty()) {
+			if (beanNames.length == 0) {
 				return;
 			}
-			else if (userDetailsServices.size() > 1) {
-				List<String> beanNames = userDetailsServices.stream().map(BeanWithName::getName).toList();
+			else if (beanNames.length > 1) {
 				this.logger.warn(LogMessage.format("Found %s UserDetailsService beans, with names %s. "
 						+ "Global Authentication Manager will not use a UserDetailsService for username/password login. "
-						+ "Consider publishing a single UserDetailsService bean.", userDetailsServices.size(),
-						beanNames));
+						+ "Consider publishing a single UserDetailsService bean.", beanNames.length,
+						Arrays.toString(beanNames)));
 				return;
 			}
-			UserDetailsService userDetailsService = userDetailsServices.get(0).getBean();
-			String userDetailsServiceBeanName = userDetailsServices.get(0).getName();
+			UserDetailsService userDetailsService = InitializeUserDetailsBeanManagerConfigurer.this.context
+				.getBean(beanNames[0], UserDetailsService.class);
 			PasswordEncoder passwordEncoder = getBeanOrNull(PasswordEncoder.class);
 			UserDetailsPasswordService passwordManager = getBeanOrNull(UserDetailsPasswordService.class);
 			CompromisedPasswordChecker passwordChecker = getBeanOrNull(CompromisedPasswordChecker.class);
@@ -111,8 +110,7 @@ class InitializeUserDetailsBeanManagerConfigurer extends GlobalAuthenticationCon
 			provider.afterPropertiesSet();
 			auth.authenticationProvider(provider);
 			this.logger.info(LogMessage.format(
-					"Global AuthenticationManager configured with UserDetailsService bean with name %s",
-					userDetailsServiceBeanName));
+					"Global AuthenticationManager configured with UserDetailsService bean with name %s", beanNames[0]));
 		}

 		/**
@@ -127,41 +125,6 @@ class InitializeUserDetailsBeanManagerConfigurer extends GlobalAuthenticationCon
 			return InitializeUserDetailsBeanManagerConfigurer.this.context.getBean(beanNames[0], type);
 		}

-		/**
-		 * @return a list of beans of the requested class, along with their names. If
-		 * there are no registered beans of that type, the list is empty.
-		 */
-		private <T> List<BeanWithName<T>> getBeansWithName(Class<T> type) {
-			List<BeanWithName<T>> beanWithNames = new ArrayList<>();
-			String[] beanNames = InitializeUserDetailsBeanManagerConfigurer.this.context.getBeanNamesForType(type);
-			for (String beanName : beanNames) {
-				T bean = InitializeUserDetailsBeanManagerConfigurer.this.context.getBean(beanName, type);
-				beanWithNames.add(new BeanWithName<T>(bean, beanName));
-			}
-			return beanWithNames;
-		}
-
-		static class BeanWithName<T> {
-
-			private final T bean;
-
-			private final String name;
-
-			BeanWithName(T bean, String name) {
-				this.bean = bean;
-				this.name = name;
-			}
-
-			T getBean() {
-				return this.bean;
-			}
-
-			String getName() {
-				return this.name;
-			}
-
-		}
-
 	}

 }
@@ -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;
 			}
@@ -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() {
@@ -0,0 +1,65 @@
+/*
+ * 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.config.web.server;
+
+import org.springframework.http.converter.GenericHttpMessageConverter;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.json.GsonHttpMessageConverter;
+import org.springframework.http.converter.json.JsonbHttpMessageConverter;
+import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
+import org.springframework.util.ClassUtils;
+
+/**
+ * Utility methods for {@link HttpMessageConverter}'s.
+ *
+ * @author Joe Grandja
+ * @author luamas
+ * @since 5.1
+ */
+final class HttpMessageConverters {
+
+	private static final boolean jackson2Present;
+
+	private static final boolean gsonPresent;
+
+	private static final boolean jsonbPresent;
+
+	static {
+		ClassLoader classLoader = HttpMessageConverters.class.getClassLoader();
+		jackson2Present = ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper", classLoader)
+				&& ClassUtils.isPresent("com.fasterxml.jackson.core.JsonGenerator", classLoader);
+		gsonPresent = ClassUtils.isPresent("com.google.gson.Gson", classLoader);
+		jsonbPresent = ClassUtils.isPresent("jakarta.json.bind.Jsonb", classLoader);
+	}
+
+	private HttpMessageConverters() {
+	}
+
+	static GenericHttpMessageConverter<Object> getJsonMessageConverter() {
+		if (jackson2Present) {
+			return new MappingJackson2HttpMessageConverter();
+		}
+		if (gsonPresent) {
+			return new GsonHttpMessageConverter();
+		}
+		if (jsonbPresent) {
+			return new JsonbHttpMessageConverter();
+		}
+		return null;
+	}
+
+}
@@ -0,0 +1,95 @@
+/*
+ * 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.config.web.server;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+import org.jetbrains.annotations.NotNull;
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpOutputMessage;
+import org.springframework.http.MediaType;
+import org.springframework.http.codec.HttpMessageEncoder;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.security.oauth2.core.OAuth2Error;
+import org.springframework.util.MimeType;
+
+class OAuth2ErrorEncoder implements HttpMessageEncoder<OAuth2Error> {
+
+	private final HttpMessageConverter<Object> messageConverter = HttpMessageConverters.getJsonMessageConverter();
+
+	@NotNull
+	@Override
+	public List<MediaType> getStreamingMediaTypes() {
+		return List.of();
+	}
+
+	@Override
+	public boolean canEncode(ResolvableType elementType, MimeType mimeType) {
+		return getEncodableMimeTypes().contains(mimeType);
+	}
+
+	@NotNull
+	@Override
+	public Flux<DataBuffer> encode(Publisher<? extends OAuth2Error> error, DataBufferFactory bufferFactory,
+			ResolvableType elementType, MimeType mimeType, Map<String, Object> hints) {
+		return Mono.from(error).flatMap((data) -> {
+			ByteArrayHttpOutputMessage bytes = new ByteArrayHttpOutputMessage();
+			try {
+				this.messageConverter.write(data, MediaType.APPLICATION_JSON, bytes);
+				return Mono.just(bytes.getBody().toByteArray());
+			}
+			catch (IOException ex) {
+				return Mono.error(ex);
+			}
+		}).map(bufferFactory::wrap).flux();
+	}
+
+	@NotNull
+	@Override
+	public List<MimeType> getEncodableMimeTypes() {
+		return List.of(MediaType.APPLICATION_JSON);
+	}
+
+	private static class ByteArrayHttpOutputMessage implements HttpOutputMessage {
+
+		private final ByteArrayOutputStream body = new ByteArrayOutputStream();
+
+		@NotNull
+		@Override
+		public ByteArrayOutputStream getBody() {
+			return this.body;
+		}
+
+		@NotNull
+		@Override
+		public HttpHeaders getHeaders() {
+			return new HttpHeaders();
+		}
+
+	}
+
+}
@@ -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;
+		};
 	}

 	/**
@@ -16,16 +16,17 @@

 package org.springframework.security.config.web.server;

-import java.nio.charset.StandardCharsets;
+import java.util.Collections;

 import jakarta.servlet.http.HttpServletResponse;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;

-import org.springframework.core.io.buffer.DataBuffer;
-import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.core.ResolvableType;
+import org.springframework.http.MediaType;
+import org.springframework.http.codec.EncoderHttpMessageWriter;
+import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.security.authentication.AuthenticationManager;
 import org.springframework.security.authentication.AuthenticationServiceException;
 import org.springframework.security.authentication.ReactiveAuthenticationManager;
@@ -62,6 +63,9 @@ class OidcBackChannelLogoutWebFilter implements WebFilter {

 	private ServerLogoutHandler logoutHandler = new OidcBackChannelServerLogoutHandler();

+	private final HttpMessageWriter<OAuth2Error> errorHttpMessageConverter = new EncoderHttpMessageWriter<>(
+			new OAuth2ErrorEncoder());
+
 	/**
 	 * Construct an {@link OidcBackChannelLogoutWebFilter}
 	 * @param authenticationConverter the {@link AuthenticationConverter} for deriving
@@ -84,7 +88,7 @@ class OidcBackChannelLogoutWebFilter implements WebFilter {
 			if (ex instanceof AuthenticationServiceException) {
 				return Mono.error(ex);
 			}
-			return handleAuthenticationFailure(exchange.getResponse(), ex).then(Mono.empty());
+			return handleAuthenticationFailure(exchange, ex).then(Mono.empty());
 		})
 			.switchIfEmpty(chain.filter(exchange).then(Mono.empty()))
 			.flatMap(this.authenticationManager::authenticate)
@@ -93,7 +97,7 @@ class OidcBackChannelLogoutWebFilter implements WebFilter {
 				if (ex instanceof AuthenticationServiceException) {
 					return Mono.error(ex);
 				}
-				return handleAuthenticationFailure(exchange.getResponse(), ex).then(Mono.empty());
+				return handleAuthenticationFailure(exchange, ex).then(Mono.empty());
 			})
 			.flatMap((authentication) -> {
 				WebFilterExchange webFilterExchange = new WebFilterExchange(exchange, chain);
@@ -101,19 +105,12 @@ class OidcBackChannelLogoutWebFilter implements WebFilter {
 			});
 	}

-	private Mono<Void> handleAuthenticationFailure(ServerHttpResponse response, Exception ex) {
+	private Mono<Void> handleAuthenticationFailure(ServerWebExchange exchange, Exception ex) {
 		this.logger.debug("Failed to process OIDC Back-Channel Logout", ex);
-		response.setRawStatusCode(HttpServletResponse.SC_BAD_REQUEST);
-		OAuth2Error error = oauth2Error(ex);
-		byte[] bytes = String.format("""
-				{
-					"error_code": "%s",
-					"error_description": "%s",
-					"error_uri: "%s"
-				}
-				""", error.getErrorCode(), error.getDescription(), error.getUri()).getBytes(StandardCharsets.UTF_8);
-		DataBuffer buffer = response.bufferFactory().wrap(bytes);
-		return response.writeWith(Flux.just(buffer));
+		exchange.getResponse().setRawStatusCode(HttpServletResponse.SC_BAD_REQUEST);
+		return this.errorHttpMessageConverter.write(Mono.just(oauth2Error(ex)), ResolvableType.forClass(Object.class),
+				ResolvableType.forClass(Object.class), MediaType.APPLICATION_JSON, exchange.getRequest(),
+				exchange.getResponse(), Collections.emptyMap());
 	}

 	private OAuth2Error oauth2Error(Exception ex) {
@@ -16,8 +16,8 @@

 package org.springframework.security.config.web.server;

-import java.nio.charset.StandardCharsets;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -25,14 +25,15 @@ import java.util.concurrent.atomic.AtomicInteger;
 import jakarta.servlet.http.HttpServletResponse;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;

-import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.ResolvableType;
 import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.codec.EncoderHttpMessageWriter;
+import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.server.reactive.ServerHttpRequest;
-import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.oauth2.client.oidc.authentication.logout.OidcLogoutToken;
 import org.springframework.security.oauth2.client.oidc.server.session.InMemoryReactiveOidcSessionRegistry;
@@ -44,6 +45,7 @@ import org.springframework.security.web.server.WebFilterExchange;
 import org.springframework.security.web.server.authentication.logout.ServerLogoutHandler;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.util.UriComponents;
 import org.springframework.web.util.UriComponentsBuilder;

@@ -63,6 +65,9 @@ final class OidcBackChannelServerLogoutHandler implements ServerLogoutHandler {

 	private ReactiveOidcSessionRegistry sessionRegistry = new InMemoryReactiveOidcSessionRegistry();

+	private final HttpMessageWriter<OAuth2Error> errorHttpMessageConverter = new EncoderHttpMessageWriter<>(
+			new OAuth2ErrorEncoder());
+
 	private WebClient web = WebClient.create();

 	private String logoutUri = "{baseScheme}://localhost{basePort}/logout";
@@ -97,7 +102,7 @@ final class OidcBackChannelServerLogoutHandler implements ServerLogoutHandler {
 						totalCount.intValue()));
 			}
 			if (!list.isEmpty()) {
-				return handleLogoutFailure(exchange.getExchange().getResponse(), oauth2Error(list));
+				return handleLogoutFailure(exchange.getExchange(), oauth2Error(list));
 			}
 			else {
 				return Mono.empty();
@@ -148,17 +153,11 @@ final class OidcBackChannelServerLogoutHandler implements ServerLogoutHandler {
 				"https://openid.net/specs/openid-connect-backchannel-1_0.html#Validation");
 	}

-	private Mono<Void> handleLogoutFailure(ServerHttpResponse response, OAuth2Error error) {
-		response.setRawStatusCode(HttpServletResponse.SC_BAD_REQUEST);
-		byte[] bytes = String.format("""
-				{
-					"error_code": "%s",
-					"error_description": "%s",
-					"error_uri: "%s"
-				}
-				""", error.getErrorCode(), error.getDescription(), error.getUri()).getBytes(StandardCharsets.UTF_8);
-		DataBuffer buffer = response.bufferFactory().wrap(bytes);
-		return response.writeWith(Flux.just(buffer));
+	private Mono<Void> handleLogoutFailure(ServerWebExchange exchange, OAuth2Error error) {
+		exchange.getResponse().setRawStatusCode(HttpServletResponse.SC_BAD_REQUEST);
+		return this.errorHttpMessageConverter.write(Mono.just(error), ResolvableType.forClass(Object.class),
+				ResolvableType.forClass(Object.class), MediaType.APPLICATION_JSON, exchange.getRequest(),
+				exchange.getResponse(), Collections.emptyMap());
 	}

 	/**
@@ -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));
 	}

@@ -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 {

@@ -50,6 +50,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.annotation.Order;
 import org.springframework.http.ResponseCookie;
 import org.springframework.http.client.reactive.ClientHttpConnector;
@@ -74,6 +75,8 @@ 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;
@@ -97,6 +100,7 @@ import org.springframework.web.server.WebSession;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;

 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.hasValue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.atLeastOnce;
@@ -195,7 +199,10 @@ public class OidcLogoutSpecTests {
 			.body(BodyInserters.fromFormData("logout_token", "invalid"))
 			.exchange()
 			.expectStatus()
-			.isBadRequest();
+			.isBadRequest()
+			.expectBody(new ParameterizedTypeReference<Map<String, String>>() {
+			})
+			.value(hasValue("invalid_request"));
 		this.test.get().uri("/token/logout").cookie("SESSION", session).exchange().expectStatus().isOk();
 	}

@@ -262,9 +269,10 @@ public class OidcLogoutSpecTests {
 			.exchange()
 			.expectStatus()
 			.isBadRequest()
-			.expectBody(String.class)
-			.value(containsString("partial_logout"))
-			.value(containsString("not all sessions were terminated"));
+			.expectBody(new ParameterizedTypeReference<Map<String, String>>() {
+			})
+			.value(hasValue("partial_logout"))
+			.value(hasValue(containsString("not all sessions were terminated")));
 		this.test.get().uri("/token/logout").cookie("SESSION", one).exchange().expectStatus().isOk();
 	}

@@ -694,8 +702,9 @@ 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 +713,9 @@ 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();
 		}
 	}
@@ -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 {
@@ -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/v0.4.18/ui-bundle.zip
    snapshot: true
 runtime:
  log:
@@ -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.
@@ -14,6 +14,7 @@ The following image shows the typical layering of the handlers for a single HTTP

 .FilterChain
 [[servlet-filterchain-figure]]
+[.invert-dark]
 image::{figures}/filterchain.png[]

 The client sends a request to the application, and the container creates a `FilterChain`, which contains the `Filter` instances and `Servlet` that should process the `HttpServletRequest`, based on the path of the request URI.
@@ -66,6 +67,7 @@ Here is a picture of how `DelegatingFilterProxy` fits into the <<servlet-filters

 .DelegatingFilterProxy
 [[servlet-delegatingfilterproxy-figure]]
+[.invert-dark]
 image::{figures}/delegatingfilterproxy.png[]

 `DelegatingFilterProxy` looks up __Bean Filter~0~__ from the `ApplicationContext` and then invokes __Bean Filter~0~__.
@@ -113,6 +115,7 @@ The following image shows the role of `FilterChainProxy`.

 .FilterChainProxy
 [[servlet-filterchainproxy-figure]]
+[.invert-dark]
 image::{figures}/filterchainproxy.png[]

 [[servlet-securityfilterchain]]
@@ -124,6 +127,7 @@ The following image shows the role of `SecurityFilterChain`.

 .SecurityFilterChain
 [[servlet-securityfilterchain-figure]]
+[.invert-dark]
 image::{figures}/securityfilterchain.png[]

 The <<servlet-security-filters,Security Filters>> in `SecurityFilterChain` are typically Beans, but they are registered with `FilterChainProxy` instead of <<servlet-delegatingfilterproxy>>.
@@ -145,6 +149,7 @@ The following image shows multiple `SecurityFilterChain` instances:

 .Multiple SecurityFilterChain
 [[servlet-multi-securityfilterchain-figure]]
+[.invert-dark]
 image::{figures}/multi-securityfilterchain.png[]

 In the <<servlet-multi-securityfilterchain-figure>> figure, `FilterChainProxy` decides which `SecurityFilterChain` should be used.
@@ -398,6 +403,7 @@ The {security-api-url}org/springframework/security/web/access/ExceptionTranslati

 The following image shows the relationship of `ExceptionTranslationFilter` to other components:

+[.invert-dark]
 image::{figures}/exceptiontranslationfilter.png[]


@@ -22,6 +22,7 @@ This also gives a good idea of the high level flow of authentication and how pie
 At the heart of Spring Security's authentication model is the `SecurityContextHolder`.
 It contains the <<servlet-authentication-securitycontext>>.

+[.invert-dark]
 image::{figures}/securitycontextholder.png[]

 The `SecurityContextHolder` is where Spring Security stores the details of who is xref:features/authentication/index.adoc#authentication[authenticated].
@@ -175,6 +176,7 @@ While the implementation of `AuthenticationManager` could be anything, the most
 Each `AuthenticationProvider` has an opportunity to indicate that authentication should be successful, fail, or indicate it cannot make a decision and allow a downstream `AuthenticationProvider` to decide.
 If none of the configured `AuthenticationProvider` instances can authenticate, authentication fails with a `ProviderNotFoundException`, which is a special `AuthenticationException` that indicates that the `ProviderManager` was not configured to support the type of `Authentication` that was passed into it.

+[.invert-dark]
 image::{figures}/providermanager.png[]

 In practice each `AuthenticationProvider` knows how to perform a specific type of authentication.
@@ -184,11 +186,13 @@ This lets each `AuthenticationProvider` do a very specific type of authenticatio
 `ProviderManager` also allows configuring an optional parent `AuthenticationManager`, which is consulted in the event that no `AuthenticationProvider` can perform authentication.
 The parent can be any type of `AuthenticationManager`, but it is often an instance of `ProviderManager`.

+[.invert-dark]
 image::{figures}/providermanager-parent.png[]

 In fact, multiple `ProviderManager` instances might share the same parent `AuthenticationManager`.
 This is somewhat common in scenarios where there are multiple xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] instances that have some authentication in common (the shared parent `AuthenticationManager`), but also different authentication mechanisms (the different `ProviderManager` instances).

+[.invert-dark]
 image::{figures}/providermanagers-parent.png[]

 [[servlet-authentication-providermanager-erasing-credentials]]
@@ -234,6 +238,7 @@ Before the credentials can be authenticated, Spring Security typically requests

 Next, the `AbstractAuthenticationProcessingFilter` can authenticate any authentication requests that are submitted to it.

+[.invert-dark]
 image::{figures}/abstractauthenticationprocessingfilter.png[]

 image:{icondir}/number_1.png[] When the user submits their credentials, the `AbstractAuthenticationProcessingFilter` creates an <<servlet-authentication-authentication,`Authentication`>> from the `HttpServletRequest` to be authenticated.
@@ -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::
@@ -9,6 +9,7 @@ This section describes how HTTP Basic Authentication works within Spring Securit
 First, we see the https://tools.ietf.org/html/rfc7235#section-4.1[WWW-Authenticate] header is sent back to an unauthenticated client:

 .Sending WWW-Authenticate Header
+[.invert-dark]
 image::{figures}/basicauthenticationentrypoint.png[]

 The preceding figure builds off our xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] diagram.
@@ -26,6 +27,7 @@ The following image shows the flow for the username and password being processed

 [[servlet-authentication-basicauthenticationfilter]]
 .Authenticating Username and Password
+[.invert-dark]
 image::{figures}/basicauthenticationfilter.png[]

 The preceding figure builds off our xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] diagram.
@@ -8,6 +8,7 @@ This section examines how `DaoAuthenticationProvider` works within Spring Securi
 The following figure explains the workings of the xref:servlet/authentication/architecture.adoc#servlet-authentication-authenticationmanager[`AuthenticationManager`] in figures from the xref:servlet/authentication/passwords/index.adoc#servlet-authentication-unpwd-input[Reading the Username & Password] section.

 .`DaoAuthenticationProvider` Usage
+[.invert-dark]
 image::{figures}/daoauthenticationprovider.png[]

 image:{icondir}/number_1.png[] The authentication `Filter` from the xref:servlet/authentication/passwords/index.adoc#servlet-authentication-unpwd-input[Reading the Username & Password] section passes a `UsernamePasswordAuthenticationToken` to the `AuthenticationManager`, which is implemented by xref:servlet/authentication/architecture.adoc#servlet-authentication-providermanager[`ProviderManager`].
@@ -10,6 +10,7 @@ This section examines how form-based login works within Spring Security.
 First, we see how the user is redirected to the login form:

 .Redirecting to the Login Page
+[.invert-dark]
 image::{figures}/loginurlauthenticationentrypoint.png[]

 The preceding figure builds off our xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] diagram.
@@ -30,6 +31,7 @@ When the username and password are submitted, the `UsernamePasswordAuthenticatio
 The `UsernamePasswordAuthenticationFilter` extends xref:servlet/authentication/architecture.adoc#servlet-authentication-abstractprocessingfilter[AbstractAuthenticationProcessingFilter], so the following diagram should look pretty similar:

 .Authenticating Username and Password
+[.invert-dark]
 image::{figures}/usernamepasswordauthenticationfilter.png[]

 The figure builds off our xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] diagram.
@@ -191,6 +191,7 @@ In Spring Security 6, the example shown above is the default configuration.

 The {security-api-url}org/springframework/security/web/context/SecurityContextPersistenceFilter.html[`SecurityContextPersistenceFilter`] is responsible for persisting the `SecurityContext` between requests using the xref::servlet/authentication/persistence.adoc#securitycontextrepository[`SecurityContextRepository`].

+[.invert-dark]
 image::{figures}/securitycontextpersistencefilter.png[]

 image:{icondir}/number_1.png[] Before running the rest of the application, `SecurityContextPersistenceFilter` loads the `SecurityContext` from the `SecurityContextRepository` and sets it on the `SecurityContextHolder`.
@@ -212,6 +213,7 @@ To avoid these problems, the `SecurityContextPersistenceFilter` wraps both the `

 The {security-api-url}org/springframework/security/web/context/SecurityContextHolderFilter.html[`SecurityContextHolderFilter`] is responsible for loading the `SecurityContext` between requests using the xref::servlet/authentication/persistence.adoc#securitycontextrepository[`SecurityContextRepository`].

+[.invert-dark]
 image::{figures}/securitycontextholderfilter.png[]

 image:{icondir}/number_1.png[] Before running the rest of the application, `SecurityContextHolderFilter` loads the `SecurityContext` from the `SecurityContextRepository` and sets it on the `SecurityContextHolder`.
@@ -126,6 +126,7 @@ For method security, you can use `AuthorizationManagerBeforeMethodInterceptor` a

 [[authz-authorization-manager-implementations]]
 .Authorization Manager Implementations
+[.invert-dark]
 image::{figures}/authorizationhierarchy.png[]

 Using this approach, a composition of `AuthorizationManager` implementations can be polled on an authorization decision.
@@ -342,6 +343,7 @@ The following image shows the `AccessDecisionManager` interface:

 [[authz-access-voting]]
 .Voting Decision Manager
+[.invert-dark]
 image::{figures}/access-decision-voting.png[]

 By using this approach, a series of `AccessDecisionVoter` implementations are polled on an authorization decision.
@@ -402,6 +404,7 @@ For example, on the Spring web site, you can find a https://spring.io/blog/2009/

 [[authz-after-invocation]]
 .After Invocation Implementation
+[.invert-dark]
 image::{figures}/after-invocation.png[]

 Like many other parts of Spring Security, `AfterInvocationManager` has a single concrete implementation, `AfterInvocationProviderManager`, which polls a list of ``AfterInvocationProvider``s.
@@ -65,6 +65,7 @@ In many cases, your authorization rules will be more sophisticated than that, so
 This section builds on xref:servlet/architecture.adoc#servlet-architecture[Servlet Architecture and Implementation] by digging deeper into how xref:servlet/authorization/index.adoc#servlet-authorization[authorization] works at the request level in Servlet-based applications.

 .Authorize HttpServletRequest
+[.invert-dark]
 image::{figures}/authorizationfilter.png[]

 * image:{icondir}/number_1.png[] First, the `AuthorizationFilter` constructs a `Supplier` that retrieves an  xref:servlet/authentication/architecture.adoc#servlet-authentication-authentication[Authentication] from the xref:servlet/authentication/architecture.adoc#servlet-authentication-securitycontextholder[SecurityContextHolder].
@@ -115,6 +115,7 @@ open class MyCustomerService {

 A given invocation to `MyCustomerService#readCustomer` may look something like this when Method Security <<activate-method-security,is activated>>:

+[.invert-dark]
 image::{figures}/methodsecurity.png[]

 1. Spring AOP invokes its proxy method for `readCustomer`. Among the proxy's other advisors, it invokes an {security-api-url}org/springframework/security/authorization/method/AuthorizationManagerBeforeMethodInterceptor.html[`AuthorizationManagerBeforeMethodInterceptor`] that matches <<annotation-method-pointcuts,the `@PreAuthorize` pointcut>>
@@ -82,6 +82,7 @@ To learn more about CSRF protection for your application, consider the following
 CSRF protection is provided by several components that are composed within the {security-api-url}org/springframework/security/web/csrf/CsrfFilter.html[`CsrfFilter`]:

 .`CsrfFilter` Components
+[.invert-dark]
 image::{figures}/csrf.png[]

 CSRF protection is divided into two parts:
@@ -90,6 +91,7 @@ CSRF protection is divided into two parts:
 2. Determine if the request requires CSRF protection, load and validate the token, and <<csrf-access-denied-handler,handle `AccessDeniedException`>>.

 .`CsrfFilter` Processing
+[.invert-dark]
 image::{figures}/csrf-processing.png[]

 * image:{icondir}/number_1.png[] First, the {security-api-url}org/springframework/security/web/csrf/DeferredCsrfToken.html[`DeferredCsrfToken`] is loaded, which holds a reference to the <<csrf-token-repository,`CsrfTokenRepository`>> so that the persisted `CsrfToken` can be loaded later (in image:{icondir}/number_4.png[]).
@@ -205,6 +205,78 @@ This will ensure that:
 <5> Any other message of type MESSAGE or SUBSCRIBE is rejected. Due to 6 we do not need this step, but it illustrates how one can match on specific message types.
 <6> Any other Message is rejected. This is a good idea to ensure that you do not miss any messages.

+[[migrating-spel-expressions]]
+=== Migrating SpEL Expressions
+
+If you are migrating from an older version of Spring Security, your destination matchers may include SpEL expressions.
+It's recommended that these be changed to using concrete implementations of `AuthorizationManager` since this is independently testable.
+
+However, to ease migration, you can also use a class like the following:
+
+[source,java]
+----
+public final class MessageExpressionAuthorizationManager implements AuthorizationManager<MessageAuthorizationContext<?>> {
+
+	private SecurityExpressionHandler<Message<?>> expressionHandler = new DefaultMessageSecurityExpressionHandler();
+
+	private Expression expression;
+
+	public MessageExpressionAuthorizationManager(String expressionString) {
+		Assert.hasText(expressionString, "expressionString cannot be empty");
+		this.expression = this.expressionHandler.getExpressionParser().parseExpression(expressionString);
+	}
+
+	@Override
+	public AuthorizationDecision check(Supplier<Authentication> authentication, MessageAuthorizationContext<?> context) {
+		EvaluationContext ctx = this.expressionHandler.createEvaluationContext(authentication, context.getMessage());
+		boolean granted = ExpressionUtils.evaluateAsBoolean(this.expression, ctx);
+		return new ExpressionAuthorizationDecision(granted, this.expression);
+	}
+
+}
+----
+
+And specify an instance for each matcher that you cannot get migrate:
+
+[tabs]
+======
+Java::
+
+[source,java,role="primary"]
+----
+@Configuration
+public class WebSocketSecurityConfig {
+
+    @Bean
+    public AuthorizationManager<Message<?>> messageAuthorizationManager(MessageMatcherDelegatingAuthorizationManager.Builder messages) {
+        messages
+                // ...
+                .simpSubscribeDestMatchers("/topic/friends/{friend}").access(new MessageExpressionAuthorizationManager("#friends == 'john"));
+                // ...
+
+        return messages.build();
+    }
+}
+----
+
+Kotlin::
+
+[source,kotlin,role="secondary"]
+----
+@Configuration
+open class WebSocketSecurityConfig {
+    fun messageAuthorizationManager(messages: MessageMatcherDelegatingAuthorizationManager.Builder): AuthorizationManager<Message<?> {
+        messages
+            // ..
+            .simpSubscribeDestMatchers("/topic/friends/{friends}").access(MessageExpressionAuthorizationManager("#friends == 'john"))
+            // ...
+
+        return messages.build()
+    }
+}
+----
+======
+
 [[websocket-authorization-notes]]
 === WebSocket Authorization Notes

@@ -21,6 +21,7 @@ Now we can consider how Bearer Token Authentication works within Spring Security
 First, we see that, as with xref:servlet/authentication/passwords/basic.adoc#servlet-authentication-basic[Basic Authentication], the https://tools.ietf.org/html/rfc7235#section-4.1[WWW-Authenticate] header is sent back to an unauthenticated client:

 .Sending WWW-Authenticate Header
+[.invert-dark]
 image::{figures}/bearerauthenticationentrypoint.png[]

 The figure above builds off our xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] diagram.
@@ -38,6 +39,7 @@ The following image shows the flow for the bearer token being processed:

 [[oauth2resourceserver-authentication-bearertokenauthenticationfilter]]
 .Authenticating Bearer Token
+[.invert-dark]
 image::{figures}/bearertokenauthenticationfilter.png[]

 The figure builds off our xref:servlet/architecture.adoc#servlet-securityfilterchain[`SecurityFilterChain`] diagram.
@@ -92,6 +92,7 @@ Let's take a look at how `JwtAuthenticationProvider` works within Spring Securit
 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
+[.invert-dark]
 image::{figures}/jwtauthenticationprovider.png[]

 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`].
@@ -88,6 +88,7 @@ Let's take a look at how `OpaqueTokenAuthenticationProvider` works within Spring
 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
+[.invert-dark]
 image::{figures}/opaquetokenauthenticationprovider.png[]

 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`].
@@ -7,6 +7,7 @@ First, we see that, like <<oauth2login, OAuth 2.0 Login>>, Spring Security takes
 It does this through a series of redirects:

 .Redirecting to Asserting Party Authentication
+[.invert-dark]
 image::{figures}/saml2webssoauthenticationrequestfilter.png[]

 [NOTE]
@@ -34,6 +35,7 @@ The following image shows how Spring Security authenticates a `<saml2:Response>`

 [[servlet-saml2login-authentication-saml2webssoauthenticationfilter]]
 .Authenticating a `<saml2:Response>`
+[.invert-dark]
 image::{figures}/saml2webssoauthenticationfilter.png[]

 [NOTE]
@@ -1,8 +1,8 @@
 {
  "dependencies": {
-    "antora": "3.2.0-alpha.6",
+    "antora": "3.2.0-alpha.8",
    "@antora/atlas-extension": "1.0.0-alpha.2",
-    "@antora/collector-extension": "1.0.0-beta.3",
+    "@antora/collector-extension": "1.0.1",
    "@asciidoctor/tabs": "1.0.0-beta.6",
    "@springio/antora-extensions": "1.14.2",
    "@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>
@@ -1,5 +1,5 @@
 springBootVersion=3.1.1
-version=6.3.4
+version=6.3.6
 samplesBranch=6.3.x
 org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.parallel=true
@@ -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 = "6.1.16"

 [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:2023.0.13"
 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:2024.0.7"
+org-springframework-ldap-spring-ldap-core = "org.springframework.ldap:spring-ldap-core:3.2.10"
 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"

@@ -95,11 +95,11 @@ net-sourceforge-saxon-saxon = "net.sourceforge.saxon:saxon:9.1.0.8"
 org-yaml-snakeyaml = "org.yaml:snakeyaml:1.33"
 org-apache-commons-commons-io = "org.apache.commons:commons-io:1.3.2"
 io-github-gradle-nexus-publish-plugin = "io.github.gradle-nexus:publish-plugin:1.3.0"
-org-gretty-gretty = "org.gretty:gretty:4.1.5"
+org-gretty-gretty = "org.gretty:gretty:4.1.6"
 com-github-ben-manes-gradle-versions-plugin = "com.github.ben-manes:gradle-versions-plugin:0.51.0"
 com-github-spullara-mustache-java-compiler = "com.github.spullara.mustache.java:compiler:0.9.14"
 org-hidetake-gradle-ssh-plugin = "org.hidetake:gradle-ssh-plugin:2.10.1"
-org-jfrog-buildinfo-build-info-extractor-gradle = "org.jfrog.buildinfo:build-info-extractor-gradle:4.33.22"
+org-jfrog-buildinfo-build-info-extractor-gradle = "org.jfrog.buildinfo:build-info-extractor-gradle:4.33.23"
 org-sonarsource-scanner-gradle-sonarqube-gradle-plugin = "org.sonarsource.scanner.gradle:sonarqube-gradle-plugin:2.8.0.1969"
 org-instancio-instancio-junit = "org.instancio:instancio-junit:3.7.1"

@@ -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;
 	}

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

@@ -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 2002-2019 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.
@@ -80,7 +80,13 @@ public final class InMemoryOAuth2AuthorizedClientService implements OAuth2Author
 		if (registration == null) {
 			return null;
 		}
-		return (T) this.authorizedClients.get(new OAuth2AuthorizedClientId(clientRegistrationId, principalName));
+		OAuth2AuthorizedClient cachedAuthorizedClient = this.authorizedClients
+			.get(new OAuth2AuthorizedClientId(clientRegistrationId, principalName));
+		if (cachedAuthorizedClient == null) {
+			return null;
+		}
+		return (T) new OAuth2AuthorizedClient(registration, cachedAuthorizedClient.getPrincipalName(),
+				cachedAuthorizedClient.getAccessToken(), cachedAuthorizedClient.getRefreshToken());
 	}

 	@Override
@@ -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.
@@ -62,8 +62,15 @@ public final class InMemoryReactiveOAuth2AuthorizedClientService implements Reac
 		Assert.hasText(clientRegistrationId, "clientRegistrationId cannot be empty");
 		Assert.hasText(principalName, "principalName cannot be empty");
 		return (Mono<T>) this.clientRegistrationRepository.findByRegistrationId(clientRegistrationId)
-			.map((clientRegistration) -> new OAuth2AuthorizedClientId(clientRegistrationId, principalName))
-			.flatMap((identifier) -> Mono.justOrEmpty(this.authorizedClients.get(identifier)));
+			.mapNotNull((clientRegistration) -> {
+				OAuth2AuthorizedClientId id = new OAuth2AuthorizedClientId(clientRegistrationId, principalName);
+				OAuth2AuthorizedClient cachedAuthorizedClient = this.authorizedClients.get(id);
+				if (cachedAuthorizedClient == null) {
+					return null;
+				}
+				return new OAuth2AuthorizedClient(clientRegistration, cachedAuthorizedClient.getPrincipalName(),
+						cachedAuthorizedClient.getAccessToken(), cachedAuthorizedClient.getRefreshToken());
+			});
 	}

 	@Override
@@ -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 2002-2019 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.
@@ -18,22 +18,25 @@ package org.springframework.security.oauth2.client;

 import java.util.Collections;
 import java.util.Map;
+import java.util.function.Consumer;

 import org.junit.jupiter.api.Test;

+import org.springframework.security.authentication.TestingAuthenticationToken;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.oauth2.client.registration.ClientRegistration;
 import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
 import org.springframework.security.oauth2.client.registration.InMemoryClientRegistrationRepository;
 import org.springframework.security.oauth2.client.registration.TestClientRegistrations;
 import org.springframework.security.oauth2.core.OAuth2AccessToken;
+import org.springframework.security.oauth2.core.OAuth2RefreshToken;

 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.assertj.core.api.Assertions.assertThatObject;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.BDDMockito.given;
-import static org.mockito.Mockito.mock;
+import static org.mockito.BDDMockito.mock;

 /**
 * Tests for {@link InMemoryOAuth2AuthorizedClientService}.
@@ -79,9 +82,11 @@ public class InMemoryOAuth2AuthorizedClientServiceTests {
 	@Test
 	public void constructorWhenAuthorizedClientsProvidedThenUseProvidedAuthorizedClients() {
 		String registrationId = this.registration3.getRegistrationId();
+		OAuth2AuthorizedClient authorizedClient = new OAuth2AuthorizedClient(this.registration3, this.principalName1,
+				mock(OAuth2AccessToken.class));
 		Map<OAuth2AuthorizedClientId, OAuth2AuthorizedClient> authorizedClients = Collections.singletonMap(
 				new OAuth2AuthorizedClientId(this.registration3.getRegistrationId(), this.principalName1),
-				mock(OAuth2AuthorizedClient.class));
+				authorizedClient);
 		ClientRegistrationRepository clientRegistrationRepository = mock(ClientRegistrationRepository.class);
 		given(clientRegistrationRepository.findByRegistrationId(eq(registrationId))).willReturn(this.registration3);
 		InMemoryOAuth2AuthorizedClientService authorizedClientService = new InMemoryOAuth2AuthorizedClientService(
@@ -124,7 +129,35 @@ public class InMemoryOAuth2AuthorizedClientServiceTests {
 		this.authorizedClientService.saveAuthorizedClient(authorizedClient, authentication);
 		OAuth2AuthorizedClient loadedAuthorizedClient = this.authorizedClientService
 			.loadAuthorizedClient(this.registration1.getRegistrationId(), this.principalName1);
-		assertThat(loadedAuthorizedClient).isEqualTo(authorizedClient);
+		assertThat(loadedAuthorizedClient).satisfies(isEqualTo(authorizedClient));
+	}
+
+	@Test
+	public void loadAuthorizedClientWhenClientRegistrationIsUpdatedThenReturnAuthorizedClientWithUpdatedClientRegistration() {
+		ClientRegistration updatedRegistration = ClientRegistration.withClientRegistration(this.registration1)
+			.clientSecret("updated secret")
+			.build();
+
+		ClientRegistrationRepository clientRegistrationRepository = mock(ClientRegistrationRepository.class);
+		given(clientRegistrationRepository.findByRegistrationId(this.registration1.getRegistrationId()))
+			.willReturn(this.registration1, updatedRegistration);
+
+		InMemoryOAuth2AuthorizedClientService authorizedClientService = new InMemoryOAuth2AuthorizedClientService(
+				clientRegistrationRepository);
+
+		OAuth2AuthorizedClient cachedAuthorizedClient = new OAuth2AuthorizedClient(this.registration1,
+				this.principalName1, mock(OAuth2AccessToken.class), mock(OAuth2RefreshToken.class));
+		authorizedClientService.saveAuthorizedClient(cachedAuthorizedClient,
+				new TestingAuthenticationToken(this.principalName1, null));
+
+		OAuth2AuthorizedClient authorizedClientWithUpdatedRegistration = new OAuth2AuthorizedClient(updatedRegistration,
+				this.principalName1, mock(OAuth2AccessToken.class), mock(OAuth2RefreshToken.class));
+		OAuth2AuthorizedClient firstLoadedClient = authorizedClientService
+			.loadAuthorizedClient(this.registration1.getRegistrationId(), this.principalName1);
+		OAuth2AuthorizedClient secondLoadedClient = authorizedClientService
+			.loadAuthorizedClient(this.registration1.getRegistrationId(), this.principalName1);
+		assertThat(firstLoadedClient).satisfies(isEqualTo(cachedAuthorizedClient));
+		assertThat(secondLoadedClient).satisfies(isEqualTo(authorizedClientWithUpdatedRegistration));
 	}

 	@Test
@@ -148,7 +181,7 @@ public class InMemoryOAuth2AuthorizedClientServiceTests {
 		this.authorizedClientService.saveAuthorizedClient(authorizedClient, authentication);
 		OAuth2AuthorizedClient loadedAuthorizedClient = this.authorizedClientService
 			.loadAuthorizedClient(this.registration3.getRegistrationId(), this.principalName2);
-		assertThat(loadedAuthorizedClient).isEqualTo(authorizedClient);
+		assertThat(loadedAuthorizedClient).satisfies(isEqualTo(authorizedClient));
 	}

 	@Test
@@ -180,4 +213,38 @@ public class InMemoryOAuth2AuthorizedClientServiceTests {
 		assertThat(loadedAuthorizedClient).isNull();
 	}

+	private static Consumer<OAuth2AuthorizedClient> isEqualTo(OAuth2AuthorizedClient expected) {
+		return (actual) -> {
+			assertThat(actual).isNotNull();
+			assertThat(actual.getClientRegistration().getRegistrationId())
+				.isEqualTo(expected.getClientRegistration().getRegistrationId());
+			assertThat(actual.getClientRegistration().getClientName())
+				.isEqualTo(expected.getClientRegistration().getClientName());
+			assertThat(actual.getClientRegistration().getRedirectUri())
+				.isEqualTo(expected.getClientRegistration().getRedirectUri());
+			assertThat(actual.getClientRegistration().getAuthorizationGrantType())
+				.isEqualTo(expected.getClientRegistration().getAuthorizationGrantType());
+			assertThat(actual.getClientRegistration().getClientAuthenticationMethod())
+				.isEqualTo(expected.getClientRegistration().getClientAuthenticationMethod());
+			assertThat(actual.getClientRegistration().getClientId())
+				.isEqualTo(expected.getClientRegistration().getClientId());
+			assertThat(actual.getClientRegistration().getClientSecret())
+				.isEqualTo(expected.getClientRegistration().getClientSecret());
+			assertThat(actual.getPrincipalName()).isEqualTo(expected.getPrincipalName());
+			assertThat(actual.getAccessToken().getTokenType()).isEqualTo(expected.getAccessToken().getTokenType());
+			assertThat(actual.getAccessToken().getTokenValue()).isEqualTo(expected.getAccessToken().getTokenValue());
+			assertThat(actual.getAccessToken().getIssuedAt()).isEqualTo(expected.getAccessToken().getIssuedAt());
+			assertThat(actual.getAccessToken().getExpiresAt()).isEqualTo(expected.getAccessToken().getExpiresAt());
+			assertThat(actual.getAccessToken().getScopes()).isEqualTo(expected.getAccessToken().getScopes());
+			if (expected.getRefreshToken() != null) {
+				assertThat(actual.getRefreshToken()).isNotNull();
+				assertThat(actual.getRefreshToken().getTokenValue())
+					.isEqualTo(expected.getRefreshToken().getTokenValue());
+				assertThat(actual.getRefreshToken().getIssuedAt()).isEqualTo(expected.getRefreshToken().getIssuedAt());
+				assertThat(actual.getRefreshToken().getExpiresAt())
+					.isEqualTo(expected.getRefreshToken().getExpiresAt());
+			}
+		};
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 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.
@@ -18,12 +18,14 @@ package org.springframework.security.oauth2.client;

 import java.time.Duration;
 import java.time.Instant;
+import java.util.function.Consumer;

 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;

@@ -34,7 +36,9 @@ import org.springframework.security.oauth2.client.registration.ReactiveClientReg
 import org.springframework.security.oauth2.core.AuthorizationGrantType;
 import org.springframework.security.oauth2.core.ClientAuthenticationMethod;
 import org.springframework.security.oauth2.core.OAuth2AccessToken;
+import org.springframework.security.oauth2.core.OAuth2RefreshToken;

+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.mockito.BDDMockito.given;

@@ -56,8 +60,9 @@ public class InMemoryReactiveOAuth2AuthorizedClientServiceTests {

 	private Authentication principal = new TestingAuthenticationToken(this.principalName, "notused");

-	OAuth2AccessToken accessToken = new OAuth2AccessToken(OAuth2AccessToken.TokenType.BEARER, "token", Instant.now(),
-			Instant.now().plus(Duration.ofDays(1)));
+	private OAuth2AccessToken accessToken;
+
+	private OAuth2RefreshToken refreshToken;

 	// @formatter:off
 	private ClientRegistration clientRegistration = ClientRegistration.withRegistrationId(this.clientRegistrationId)
@@ -79,6 +84,11 @@ public class InMemoryReactiveOAuth2AuthorizedClientServiceTests {
 	public void setup() {
 		this.authorizedClientService = new InMemoryReactiveOAuth2AuthorizedClientService(
 				this.clientRegistrationRepository);
+
+		Instant issuedAt = Instant.now();
+		Instant expiresAt = issuedAt.plus(Duration.ofDays(1));
+		this.accessToken = new OAuth2AccessToken(OAuth2AccessToken.TokenType.BEARER, "token", issuedAt, expiresAt);
+		this.refreshToken = new OAuth2RefreshToken("refresh", issuedAt, expiresAt);
 	}

 	@Test
@@ -153,11 +163,37 @@ public class InMemoryReactiveOAuth2AuthorizedClientServiceTests {
 				.saveAuthorizedClient(authorizedClient, this.principal)
 				.then(this.authorizedClientService.loadAuthorizedClient(this.clientRegistrationId, this.principalName));
 		StepVerifier.create(saveAndLoad)
-				.expectNext(authorizedClient)
+				.assertNext(isEqualTo(authorizedClient))
 				.verifyComplete();
 		// @formatter:on
 	}

+	@Test
+	@SuppressWarnings("unchecked")
+	public void loadAuthorizedClientWhenClientRegistrationIsUpdatedThenReturnsAuthorizedClientWithUpdatedClientRegistration() {
+		ClientRegistration updatedRegistration = ClientRegistration.withClientRegistration(this.clientRegistration)
+			.clientSecret("updated secret")
+			.build();
+
+		given(this.clientRegistrationRepository.findByRegistrationId(this.clientRegistrationId))
+			.willReturn(Mono.just(this.clientRegistration), Mono.just(updatedRegistration));
+
+		OAuth2AuthorizedClient cachedAuthorizedClient = new OAuth2AuthorizedClient(this.clientRegistration,
+				this.principalName, this.accessToken, this.refreshToken);
+		OAuth2AuthorizedClient authorizedClientWithChangedRegistration = new OAuth2AuthorizedClient(updatedRegistration,
+				this.principalName, this.accessToken, this.refreshToken);
+
+		Flux<OAuth2AuthorizedClient> saveAndLoadTwice = this.authorizedClientService
+			.saveAuthorizedClient(cachedAuthorizedClient, this.principal)
+			.then(this.authorizedClientService.loadAuthorizedClient(this.clientRegistrationId, this.principalName))
+			.concatWith(
+					this.authorizedClientService.loadAuthorizedClient(this.clientRegistrationId, this.principalName));
+		StepVerifier.create(saveAndLoadTwice)
+			.assertNext(isEqualTo(cachedAuthorizedClient))
+			.assertNext(isEqualTo(authorizedClientWithChangedRegistration))
+			.verifyComplete();
+	}
+
 	@Test
 	public void saveAuthorizedClientWhenAuthorizedClientNullThenIllegalArgumentException() {
 		OAuth2AuthorizedClient authorizedClient = null;
@@ -246,4 +282,38 @@ public class InMemoryReactiveOAuth2AuthorizedClientServiceTests {
 		// @formatter:on
 	}

+	private static Consumer<OAuth2AuthorizedClient> isEqualTo(OAuth2AuthorizedClient expected) {
+		return (actual) -> {
+			assertThat(actual).isNotNull();
+			assertThat(actual.getClientRegistration().getRegistrationId())
+				.isEqualTo(expected.getClientRegistration().getRegistrationId());
+			assertThat(actual.getClientRegistration().getClientName())
+				.isEqualTo(expected.getClientRegistration().getClientName());
+			assertThat(actual.getClientRegistration().getRedirectUri())
+				.isEqualTo(expected.getClientRegistration().getRedirectUri());
+			assertThat(actual.getClientRegistration().getAuthorizationGrantType())
+				.isEqualTo(expected.getClientRegistration().getAuthorizationGrantType());
+			assertThat(actual.getClientRegistration().getClientAuthenticationMethod())
+				.isEqualTo(expected.getClientRegistration().getClientAuthenticationMethod());
+			assertThat(actual.getClientRegistration().getClientId())
+				.isEqualTo(expected.getClientRegistration().getClientId());
+			assertThat(actual.getClientRegistration().getClientSecret())
+				.isEqualTo(expected.getClientRegistration().getClientSecret());
+			assertThat(actual.getPrincipalName()).isEqualTo(expected.getPrincipalName());
+			assertThat(actual.getAccessToken().getTokenType()).isEqualTo(expected.getAccessToken().getTokenType());
+			assertThat(actual.getAccessToken().getTokenValue()).isEqualTo(expected.getAccessToken().getTokenValue());
+			assertThat(actual.getAccessToken().getIssuedAt()).isEqualTo(expected.getAccessToken().getIssuedAt());
+			assertThat(actual.getAccessToken().getExpiresAt()).isEqualTo(expected.getAccessToken().getExpiresAt());
+			assertThat(actual.getAccessToken().getScopes()).isEqualTo(expected.getAccessToken().getScopes());
+			if (expected.getRefreshToken() != null) {
+				assertThat(actual.getRefreshToken()).isNotNull();
+				assertThat(actual.getRefreshToken().getTokenValue())
+					.isEqualTo(expected.getRefreshToken().getTokenValue());
+				assertThat(actual.getRefreshToken().getIssuedAt()).isEqualTo(expected.getRefreshToken().getIssuedAt());
+				assertThat(actual.getRefreshToken().getExpiresAt())
+					.isEqualTo(expected.getRefreshToken().getExpiresAt());
+			}
+		};
+	}
+
 }
@@ -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;
 	}
@@ -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) {
@@ -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);

@@ -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));
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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 jakarta.servlet.http.Cookie;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;

+import org.springframework.http.HttpHeaders;
 import org.springframework.http.ResponseCookie;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -97,8 +98,18 @@ public final class CookieCsrfTokenRepository implements CsrfTokenRepository {

 		this.cookieCustomizer.accept(cookieBuilder);

-		Cookie cookie = mapToCookie(cookieBuilder.build());
-		response.addCookie(cookie);
+		ResponseCookie responseCookie = cookieBuilder.build();
+		if (!StringUtils.hasLength(responseCookie.getSameSite())) {
+			Cookie cookie = mapToCookie(responseCookie);
+			response.addCookie(cookie);
+		}
+		else if (request.getServletContext().getMajorVersion() > 5) {
+			Cookie cookie = mapToCookie(responseCookie);
+			response.addCookie(cookie);
+		}
+		else {
+			response.addHeader(HttpHeaders.SET_COOKIE, responseCookie.toString());
+		}

 		// Set request attribute to signal that response has blank cookie value,
 		// which allows loadToken to return null when token has been removed
@@ -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) {
@@ -16,6 +16,8 @@

 package org.springframework.security.web.server.firewall;

+import java.net.InetSocketAddress;
+import java.net.URI;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -23,6 +25,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.regex.Pattern;

@@ -33,6 +36,7 @@ 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.http.server.reactive.SslInfo;
 import org.springframework.util.Assert;
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.server.ServerWebExchange;
@@ -743,6 +747,11 @@ public class StrictServerWebExchangeFirewall implements ServerWebExchangeFirewal
 				return queryParams;
 			}

+			@Override
+			public Builder mutate() {
+				return new StrictFirewallBuilder(super.mutate());
+			}
+
 			private final class StrictFirewallHttpHeaders extends HttpHeaders {

 				private StrictFirewallHttpHeaders(HttpHeaders delegate) {
@@ -783,6 +792,61 @@ public class StrictServerWebExchangeFirewall implements ServerWebExchangeFirewal

 			}

+			private final class StrictFirewallBuilder implements Builder {
+
+				private final Builder delegate;
+
+				private StrictFirewallBuilder(Builder delegate) {
+					this.delegate = delegate;
+				}
+
+				@Override
+				public Builder method(HttpMethod httpMethod) {
+					return this.delegate.method(httpMethod);
+				}
+
+				@Override
+				public Builder uri(URI uri) {
+					return this.delegate.uri(uri);
+				}
+
+				@Override
+				public Builder path(String path) {
+					return this.delegate.path(path);
+				}
+
+				@Override
+				public Builder contextPath(String contextPath) {
+					return this.delegate.contextPath(contextPath);
+				}
+
+				@Override
+				public Builder header(String headerName, String... headerValues) {
+					return this.delegate.header(headerName, headerValues);
+				}
+
+				@Override
+				public Builder headers(Consumer<HttpHeaders> headersConsumer) {
+					return this.delegate.headers(headersConsumer);
+				}
+
+				@Override
+				public Builder sslInfo(SslInfo sslInfo) {
+					return this.delegate.sslInfo(sslInfo);
+				}
+
+				@Override
+				public Builder remoteAddress(InetSocketAddress remoteAddress) {
+					return this.delegate.remoteAddress(remoteAddress);
+				}
+
+				@Override
+				public ServerHttpRequest build() {
+					return new StrictFirewallHttpRequest(this.delegate.build());
+				}
+
+			}
+
 		}

 	}
@@ -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) == '/');
 		}
@@ -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) {
@@ -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.
@@ -17,16 +17,20 @@
 package org.springframework.security.web.csrf;

 import jakarta.servlet.http.Cookie;
+import jakarta.servlet.http.HttpServletResponse;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;

 import org.springframework.http.HttpHeaders;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.mock.web.MockServletContext;

 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.springframework.security.web.csrf.CsrfTokenAssert.assertThatCsrfToken;
@@ -447,6 +451,44 @@ class CookieCsrfTokenRepositoryTests {
 		assertThat(tokenCookie.isHttpOnly()).isEqualTo(Boolean.FALSE);
 	}

+	// gh-16173
+	@Test
+	void saveTokenWhenSameSiteAndServletVersion5ThenUsesAddHeader() {
+		HttpServletResponse response = mock(HttpServletResponse.class);
+		((MockServletContext) this.request.getServletContext()).setMajorVersion(5);
+		this.repository.setCookieCustomizer((builder) -> builder.sameSite("Strict"));
+		CsrfToken token = this.repository.generateToken(this.request);
+		this.repository.saveToken(token, this.request, response);
+		verify(response, never()).addCookie(any(Cookie.class));
+		verify(response).addHeader(any(), any());
+	}
+
+	// gh-16173
+	@Test
+	void saveTokenWhenSameSiteAndServletVersion6OrHigherThenUsesAddCookie() {
+		HttpServletResponse response = mock(HttpServletResponse.class);
+		this.repository.setCookieCustomizer((builder) -> builder.sameSite("Strict"));
+		CsrfToken token = this.repository.generateToken(this.request);
+		this.repository.saveToken(token, this.request, response);
+		verify(response).addCookie(any(Cookie.class));
+		verify(response, never()).addHeader(any(), any());
+	}
+
+	// gh-16173
+	@Test
+	void saveTokenWhenNoSameSiteThenUsesAddCookie() {
+		HttpServletResponse response = mock(HttpServletResponse.class);
+		CsrfToken token = this.repository.generateToken(this.request);
+		this.repository.saveToken(token, this.request, response);
+		verify(response).addCookie(any(Cookie.class));
+		verify(response, never()).addHeader(any(), any());
+		((MockServletContext) this.request.getServletContext()).setMajorVersion(5);
+		response = mock(HttpServletResponse.class);
+		this.repository.saveToken(token, this.request, response);
+		verify(response).addCookie(any(Cookie.class));
+		verify(response, never()).addHeader(any(), any());
+	}
+
 	@Test
 	void setCookieNameNullIllegalArgumentException() {
 		assertThatIllegalArgumentException().isThrownBy(() -> this.repository.setCookieName(null));
@@ -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();
+	}
+
 }
@@ -513,4 +513,25 @@ class StrictServerWebExchangeFirewallTests {
 		assertThat(exchange.getRequest().getHeaders().get(null)).isNull();
 	}

+	@Test
+	void getFirewalledExchangeWhenMutateThenHeadersStillFirewalled() {
+		String invalidHeaderName = "bad name";
+		this.firewall.setAllowedHeaderNames((name) -> !name.equals(invalidHeaderName));
+		ServerWebExchange exchange = getFirewalledExchange();
+		ServerWebExchange mutatedExchange = exchange.mutate().request(exchange.getRequest().mutate().build()).build();
+		HttpHeaders headers = mutatedExchange.getRequest().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class)
+			.isThrownBy(() -> headers.get(invalidHeaderName));
+	}
+
+	@Test
+	void getMutatedFirewalledExchangeGetHeaderWhenNotAllowedHeaderNameThenException() {
+		String invalidHeaderName = "bad name";
+		this.firewall.setAllowedHeaderNames((name) -> !name.equals(invalidHeaderName));
+		ServerWebExchange exchange = getFirewalledExchange();
+		HttpHeaders headers = exchange.getRequest().mutate().build().getHeaders();
+		assertThatExceptionOfType(ServerExchangeRejectedException.class)
+			.isThrownBy(() -> headers.get(invalidHeaderName));
+	}
+
 }
@@ -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");
+	}
+
 }