NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
☕
☕ Maven
Not in CISA KEV
HIGH severity

Keycloak TLS Client-Initiated Renegotiation Denial of ServiceGHSA-q8hq-4h99-fj7x

HIGH

GHSA-q8hq-4h99-fj7x is a high-severity (CVSS 7.5) CWE-770 vulnerability in org.keycloak:keycloak-quarkus-dist. A fix is available for org.keycloak:keycloak-quarkus-dist — see the affected versions and patch details below.

Also known asCVE-2025-11419
Published
Updated
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-q8hq-4h99-fj7x.

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk
0.00%0.41%0.82%1.23%0.1%0.7%May 26Aug 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected
☕org.keycloak:keycloak-quarkus-dist☕org.keycloak:keycloak-quarkus-dist☕org.keycloak:keycloak-quarkus-dist

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.keycloak:keycloak-quarkus-distall versions26.0.16org.keycloak:keycloak-quarkus-dist:26.0.16
☕Mavenorg.keycloak:keycloak-quarkus-dist≥ 26.1.0&&< 26.2.1026.2.10org.keycloak:keycloak-quarkus-dist:26.2.10
☕Mavenorg.keycloak:keycloak-quarkus-dist≥ 26.3.0&&< 26.4.126.4.1org.keycloak:keycloak-quarkus-dist:26.4.1

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-quarkus-dist, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.keycloak:keycloak-quarkus-dist to 26.0.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q8hq-4h99-fj7x is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant
Workaround published by Red Hat
To mitigate this vulnerability, configure Keycloak to reject client-initiated TLS renegotiation by adding the following Java system property to the Keycloak startup configuration: -Djdk.tls.rejectClientInitiatedRenegotiation=true This prevents unauthenticated attackers from triggering repeated TLS renegotiations and exhausting server CPU resources. Additionally, ensure that Keycloak is deployed behind proper network access controls and rate-limiting mechanisms to further reduce exposure to DoS attacks.
Source: Red Hat security advisory for GHSA-q8hq-4h99-fj7x (CC BY 4.0)
ProductFixed inAdvisory
Red Hat build of Keycloak 26.0rhbk/keycloak-operator-bundle:26.0.16-2RHSA-2025:18255
Red Hat build of Keycloak 26.0.16keycloak-serverRHSA-2025:18254
Red Hat build of Keycloak 26.2rhbk/keycloak-operator-bundle:26.2.10-2RHSA-2025:18889
Red Hat build of Keycloak 26.2.10keycloak-serverRHSA-2025:18890

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

Is GHSA-q8hq-4h99-fj7x in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works
Keycloak TLS Client-Initiated Renegotiation Denial of…