Vulnerability in Red Hat Build of Keycloak

[ Description ]Official description

A flaw was found in the HOTP authentication mechanism of the keycloak-services component, which provides identity and access management services. The issue occurs because the system validates a one-time password and updates its internal counter in two separate steps without proper locking. An attacker with a users password could exploit this timing gap to use a single one-time code to log in multiple times simultaneously.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund27 Oct 2026WID-SEC-2026-4191

  Keycloak: Multiple vulnerabilities Translated from German

  CVE-2026-117627CVE-2026-117688CVE-2026-118030+2 more CVEs

[ References ]References

• access.redhat.com/security/cve/CVE-2026-118030
• bugzilla.redhat.com/show_bug.cgi