userDetailsPasswordService cannot be null error when using ReactiveUserDetailsService

[matthew-js-porter]

Describe the bug
When using Spring Security 7.0.0-M3 and defining a ReactiveUserDetailsService the application
fails to start with error java.lang.IllegalArgumentException: userDetailsPasswordService cannot be null

To Reproduce

• start.spring.io and generate a new 4.0.0 project with webflux and security
• Add SecurityWebFilterChain and ReactiveUserDetailsService beans.
• start the application and observe the error

Expected behavior
The application should start and default a userDetailsPasswordService.

Sample
Sample Repository

[sephiroth-j]

Same here with my reactive sample app for LTPA2 and Spring Security v7.0.0.

stacktace

2025-12-07T17:36:57.688+01:00  WARN 6492 --- [  restartedMain] onfigReactiveWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.security.config.annotation.web.reactive.WebFluxSecurityConfiguration': Unsatisfied dependency expressed through method 'setSecurityWebFilterChains' parameter 0: Error creating bean with name 'springSecurityFilterChain' defined in class path resource [hello/config/WebSecurityConfig.class]: Unsatisfied dependency expressed through method 'springSecurityFilterChain' parameter 0: Error creating bean with name 'org.springframework.security.config.annotation.web.reactive.HttpSecurityConfiguration.httpSecurity' defined in class path resource [org/springframework/security/config/annotation/web/reactive/ServerHttpSecurityConfiguration.class]: Failed to instantiate [org.springframework.security.config.web.server.ServerHttpSecurity]: Factory method 'httpSecurity' threw exception with message: userDetailsPasswordService cannot be null
2025-12-07T17:36:57.693+01:00  INFO 6492 --- [  restartedMain] .s.b.a.l.ConditionEvaluationReportLogger : 

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2025-12-07T17:36:57.705+01:00 ERROR 6492 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.security.config.annotation.web.reactive.WebFluxSecurityConfiguration': Unsatisfied dependency expressed through method 'setSecurityWebFilterChains' parameter 0: Error creating bean with name 'springSecurityFilterChain' defined in class path resource [hello/config/WebSecurityConfig.class]: Unsatisfied dependency expressed through method 'springSecurityFilterChain' parameter 0: Error creating bean with name 'org.springframework.security.config.annotation.web.reactive.HttpSecurityConfiguration.httpSecurity' defined in class path resource [org/springframework/security/config/annotation/web/reactive/ServerHttpSecurityConfiguration.class]: Failed to instantiate [org.springframework.security.config.web.server.ServerHttpSecurity]: Factory method 'httpSecurity' threw exception with message: userDetailsPasswordService cannot be null
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.resolveMethodArguments(AutowiredAnnotationBeanPostProcessor.java:871) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:826) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:146) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:492) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1446) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:525) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:333) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:371) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:331) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1218) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1184) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1121) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:983) ~[spring-context-7.0.1.jar:7.0.1]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:620) ~[spring-context-7.0.1.jar:7.0.1]
	at org.springframework.boot.web.server.reactive.context.ReactiveWebServerApplicationContext.refresh(ReactiveWebServerApplicationContext.java:69) ~[spring-boot-web-server-4.0.0.jar:4.0.0]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:765) ~[spring-boot-4.0.0.jar:4.0.0]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:454) ~[spring-boot-4.0.0.jar:4.0.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:321) ~[spring-boot-4.0.0.jar:4.0.0]
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:154) ~[spring-boot-4.0.0.jar:4.0.0]
	at hello.Application.main(Application.java:28) ~[classes/:na]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
	at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:52) ~[spring-boot-devtools-4.0.0.jar:4.0.0]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'springSecurityFilterChain' defined in class path resource [hello/config/WebSecurityConfig.class]: Unsatisfied dependency expressed through method 'springSecurityFilterChain' parameter 0: Error creating bean with name 'org.springframework.security.config.annotation.web.reactive.HttpSecurityConfiguration.httpSecurity' defined in class path resource [org/springframework/security/config/annotation/web/reactive/ServerHttpSecurityConfiguration.class]: Failed to instantiate [org.springframework.security.config.web.server.ServerHttpSecurity]: Factory method 'httpSecurity' threw exception with message: userDetailsPasswordService cannot be null
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:804) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:546) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1362) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1194) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:565) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:525) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:333) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:371) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:331) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:201) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:229) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:2008) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1971) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveMultipleBeanCollection(DefaultListableBeanFactory.java:1863) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveMultipleBeans(DefaultListableBeanFactory.java:1833) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1711) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1651) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.resolveMethodArguments(AutowiredAnnotationBeanPostProcessor.java:863) ~[spring-beans-7.0.1.jar:7.0.1]
	... 24 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.security.config.annotation.web.reactive.HttpSecurityConfiguration.httpSecurity' defined in class path resource [org/springframework/security/config/annotation/web/reactive/ServerHttpSecurityConfiguration.class]: Failed to instantiate [org.springframework.security.config.web.server.ServerHttpSecurity]: Factory method 'httpSecurity' threw exception with message: userDetailsPasswordService cannot be null
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:645) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1362) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1194) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:565) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:525) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:351) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:201) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:229) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1762) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1651) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:912) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-7.0.1.jar:7.0.1]
	... 41 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.security.config.web.server.ServerHttpSecurity]: Factory method 'httpSecurity' threw exception with message: userDetailsPasswordService cannot be null
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:183) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiateWithFactoryMethod(SimpleInstantiationStrategy.java:72) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:152) ~[spring-beans-7.0.1.jar:7.0.1]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-7.0.1.jar:7.0.1]
	... 53 common frames omitted
Caused by: java.lang.IllegalArgumentException: userDetailsPasswordService cannot be null
	at org.springframework.util.Assert.notNull(Assert.java:182) ~[spring-core-7.0.1.jar:7.0.1]
	at org.springframework.security.authentication.AbstractUserDetailsReactiveAuthenticationManager.setUserDetailsPasswordService(AbstractUserDetailsReactiveAuthenticationManager.java:176) ~[spring-security-core-7.0.0.jar:7.0.0]
	at org.springframework.security.config.annotation.web.reactive.ServerHttpSecurityConfiguration.authenticationManager(ServerHttpSecurityConfiguration.java:258) ~[spring-security-config-7.0.0.jar:7.0.0]
	at org.springframework.security.config.annotation.web.reactive.ServerHttpSecurityConfiguration.httpSecurity(ServerHttpSecurityConfiguration.java:242) ~[spring-security-config-7.0.0.jar:7.0.0]
	at org.springframework.security.config.annotation.web.reactive.ServerHttpSecurityConfiguration.httpSecurity(ServerHttpSecurityConfiguration.java:163) ~[spring-security-config-7.0.0.jar:7.0.0]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:155) ~[spring-beans-7.0.1.jar:7.0.1]
	... 56 common frames omitted

[sephiroth-j]

Seems like a regression from commit 7c887d2.

In AbstractUserDetailsReactiveAuthenticationManager, the userDetailsPasswordService is now required, but not in ServerHttpSecurityConfiguration.

@rwinch, would you please take a look at this issue?

[sephiroth-j]

As a workaround, create a bean with the no-op instance ReactiveUserDetailsPasswordService.NOOP, which is used by default by AbstractUserDetailsReactiveAuthenticationManager.

import org.springframework.security.core.userdetails.ReactiveUserDetailsPasswordService;

//...

	@Bean
	ReactiveUserDetailsPasswordService userDetailsPasswordService() {
		return ReactiveUserDetailsPasswordService.NOOP;
	}