In Spring Framework versions 6.0.0 - 6.0.13, it is possible for a user to provide specially crafted HTTP requests that may cause a denial-of-service (DoS) condition.

Specifically, an application is vulnerable when all of the following are true:

• the application uses Spring MVC or Spring WebFlux
• io.micrometer:micrometer-core is on the classpath
• an ObservationRegistry is configured in the application to record observations

Typically, Spring Boot applications need the org.springframework.boot:spring-boot-actuator dependency to meet all conditions.

Spring Framework

• 6.0.0 to 6.0.13

Older versions are not affected.

Users of affected versions should apply the following mitigation.

• Spring Framework 6.0.x users should upgrade to 6.0.14.

No other steps are necessary.

As a temporary workaround, Spring Boot 3.0.x and 3.1.x users can choose to disable web framework observations with the following property: management.metrics.enable.http.server.requests=false

The issue was identified and responsibly reported by James Yuzawa.