Spring Security Advisories

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Micrometer gRPC server instrumentation DoS vulnerability

HIGH | JUNE 08, 2026 | CVE-2026-40983

Description

In Micrometer, it is possible for a user to provide specially crafted gRPC 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 a vulnerable version of io.micrometer:micrometer-core
  • an ObservationRegistry is configured in the application and it records observations
  • DefaultMeterObservationHandler is configured to output metrics from Observations or the user has a custom ObservationHandler that outputs metrics similarly to DefaultMeterObservationHandler
  • the application uses ObservationGrpcServerInterceptor to instrument its gRPC server

Affected Spring Products and Versions

Micrometer:

  • 1.16.0 - 1.16.5
  • 1.15.0 - 1.15.11

Mitigation

Users of affected versions should upgrade to the corresponding fixed version.
Fix versionAvailability
1.16.6OSS
1.16.5.1Enterprise Support Only
1.15.12OSS
1.15.11.1Enterprise Support Only

No further mitigation steps are necessary.

Credit

The issue was identified and responsibly reported by Yu Bao (@August829) - [email protected] – who works for paypal.com.

References

History

  • 2026-06-08: Initial vulnerability report published.

Reporting a vulnerability

To report a security vulnerability for a project within the Spring portfolio, see the Security Policy

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