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spring-boot v4.0.9

patch PublishedOct 22, 2026 Sourcespring-projects/spring-boot

spring-boot v4.0.9

:star: New Features

  • Add TWENTY_SEVEN to JavaVersion enum #51422

:lady_beetle: Bug Fixes

  • JWTs are rejected when issuer-uri is empty and jwk-set-uri is set #52249
  • Package manifest attributes are missing for nested jars without directory entries #52244
  • OriginTrackedPropertiesLoader drops properties whose name starts with # or ! #52207
  • OriginTrackedResource does not implement equals correctly #52205
  • Graceful shutdown of Tomcat or Jetty may call back with REQUESTS_ACTIVE when stop is called immediately after shutDownGracefully on an idle server #52195
  • Empty system property in TestPropertyValues is cleared instead of being restored to its empty value #52125
  • MongoDB fails to connect when credentials contain a space #52121
  • NettyWebServer stop may hang when called immediately after shutDownGracefully #52119
  • Authentication fails when password configured in spring.elasticsearch.uris contains a colon #52047
  • Logging can be lost when a context is paused by the test context framework #51959
  • Docker Compose support for MongoDB fails to connect when credentials contain a character that requires URL encoding #51939
  • Jersey does not use the endpoint ObjectMapper when Actuator is running on a separate port #51937
  • BasicJsonParser mishandles escaped characters in nested lists and maps #51907
  • Zero week value conversion fails with ‘intValue cannot be extracted from WEEKS’ exception #51892
  • App fails to start when using DevTools and manually configuring JDBC or R2DBC without spring-boot-jdbc or spring-boot-r2dbc #51872
  • Docker Compose support incorrectly recognizes MARIADB_ALLOW_EMPTY_PASSWORD instead of MARIADB_ALLOW_EMPTY_ROOT_PASSWORD #51870
  • Auto-configured Kotlinx Serialization JSON codec customization is not applied #51842
  • NullPointerException can be thrown when using uber jars due to a race condition in NestedJarFileResources #51744
  • DevTools does not detect a reactive web environment #51708
  • Connection fails when rabbitmq Docker Compose service is configured to use SSL #51666
  • When server.reactive.session.cookie.same-site is not set, session cookies have no SameSite attribute #51636
  • OAuth2 resource server ignores authorities-claim-delimiter when set on its own #51619
  • In a reactive web application, Cloud Foundry security integration returns a 500 rather than a 503 when the cloud controller URL is unavailable #51613
  • Some assertion messages name the wrong parameter #51568
  • SBOM-related manifest attributes are missing from Maven-packaged wars #51551
  • Docker Compose integration for RabbitMQ skips credential fallbacks when an environment variable has no value #51546
  • jarmode tools commands print stacktrace instead of an error message #51540
  • Layer temp file is not deleted when layer creation fails #51519
  • NestedByteChannel.read(ByteBuffer) incorrectly returns 0 when buffer could not be filled #51515
  • Customizer null checks in HTTP client builders assert the wrong attribute #51509
  • developmentOnly and testAndDevelopmentOnly configurations do not specify any attributes causing potential resolution problems #51492
  • SQL Server Docker Compose integration may duplicate the JDBC URL’s encrypt parameter #51467
  • SSL host config customizations may be lost during Tomcat initialization #51466
  • OAuth2ClientProperties are not available when a user-defined ClientRegistrationRepository bean is provided #51447
  • Source is not closed consistently by all JSON marshal testers #51417
  • JmsHealthIndicator leaks watchdog threads if start fails immediately #51412
  • File handle in SpringBootJoranConfigurator should be closed #51398
  • Validation of deprecated io.buildpacks.stack.id is too aggressive #51390
  • SSL host config customizations are lost when reloading SSL bundles #51290
  • Docker Compose ProcessRunner can hang or leave orphan processes #50963
  • Configuration property descriptions may be lost when building incrementally with Gradle #50489

:notebook_with_decorative_cover: Documentation

  • Fix actuator endpoint property names in Javadoc #51869
  • Fix broken links from reference documentation to external Javadoc #51815
  • Remove reference to AppOptics in the reference guide as it has retired #51807
  • Fix broken links #51791
  • Update Spring Framework reference links #51750
  • Maven plugin documentation incorrectly references remote restart property #51743
  • Update testcontainers javadoc links #51739
  • Fix documented default of spring.test.database.replace #51709
  • Correct Jackson 3 Javadoc links #51660
  • Fix typo in deprecated Pushgateway base-url property metadata #51627
  • Remove references to Spring Data Geode #51563
  • Fix typos in service containers javadoc and reference documentation #51431
  • Document support for Java 27 #51424
  • Document SAML2 back-off in WebFlux security documentation #51421
  • Remove reference to removed SpringBootWebSecurityConfiguration #51411

:hammer: Dependency Upgrades

:heart: Contributors

Thank you to all the contributors who worked on this release:

@2heunxun, @CCCLL, @CHISANW, @COBI-98, @DevJunz, @JunggiKim, @LindseyZ1205, @MacAlsandair, @SebTardif, @dlwldn30, @dmitrysulman, @fabio-grassi, @galenzo17, @icikle, @janwaleed09, @kdomo, @khopland, @ksky8864, @lavinhoque33, @msridhar, @ngocnhan-tran1996, @noojung, @ohchanKyu, @padosol, @piyushrajyadav, @rvullriede, @ryujungkyun, @scordio, @scottfrederick, @timtebeek, @vlsi, @xoruddl, @xxxxxxjun, @yyuneu, and @zhoubiao188

Source spring-projects/spring-boot · v4.0.9 · 2026-10-22 · upstream release

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Release notes are published by the upstream project and mirrored here for indexing. All rights belong to their authors.