GHSA-q8hq-4h99-fj7x: Keycloak TLS Client-Initiated Renegotiation Denial of Service

1. GitHub Advisory Database
2. GitHub Reviewed
3. CVE-2025-11419

Keycloak TLS Client-Initiated Renegotiation Denial of Service

High severity GitHub Reviewed Published Oct 27, 2025 in keycloak/keycloak • Updated Oct 27, 2025

Package

maven org.keycloak:keycloak-quarkus-dist (Maven)

Affected versions

< 26.0.16

>= 26.1.0, < 26.2.10

>= 26.3.0, < 26.4.1

Patched versions

26.0.16

26.2.10

26.4.1

Keycloak is vulnerable to a Denial of Service (DoS) attack due to the default JDK setting that permits Client-Initiated Renegotiation in TLS 1.2. An unauthenticated remote attacker can repeatedly initiate TLS renegotiation requests to exhaust server CPU resources, making the service unavailable. Immediate mitigation is available by setting the -Djdk.tls.rejectClientInitiatedRenegotiation=true Java system property in the Keycloak startup configuration.

References

• GHSA-q8hq-4h99-fj7x

Published to the GitHub Advisory Database

Oct 27, 2025

Last updated

Oct 27, 2025