Vulnerability in Red Hat Build of Keycloak

[ Description ]Official description

A flaw was found in the login theme rendering component of Keycloak. The issue occurs because the security filter responsible for cleaning user input can be bypassed, allowing a realm administrator to store malicious scripts in display fields. This could result in unauthorized JavaScript execution in the browsers of users visiting the login page, potentially leading to data exposure or session interference.

[ 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-Bund8 Oct 2026WID-SEC-2026-3849

  Keycloak: Multiple vulnerabilities Translated from German

  CVE-2026-107889CVE-2026-107623CVE-2026-107604

[ References ]References

• access.redhat.com/security/cve/CVE-2026-107889
• bugzilla.redhat.com/show_bug.cgi