Use of Client-Side Authentication in Keycloak - CVE-2026-8830
Published: September 5, 2026
Vulnerability identifier: #VU146989
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-8830
CWE-ID: CWE-603
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass configured WebAuthn policies during credential registration.
The vulnerability exists due to use of client-side authentication in the server-side processAction() when registering a WebAuthn credential. A remote user can manipulate client-side JavaScript to create a credential with parameters that do not match the realm\'s configured WebAuthn policies.
Affected software
Keycloak
Red Hat build of Keycloak
Red Hat build of Keycloak
How to mitigate CVE-2026-8830
Install security update from vendor's website.
Keycloak - update to 26.6.3
Red Hat build of Keycloak - addressed in versions 26.4.13, 26.6.3
Red Hat build of Keycloak - addressed in versions 26.4.13, 26.6.3