Keycloak WebAuthn Policy Bypass via Client JS Manipulation
CVE-2026-8830 Published on May 19, 2026
Keycloak: org.keycloak/keycloak-services: keycloak: policy bypass during webauthn credential registration via client-side javascript manipulation
A flaw was found in Keycloak. An authenticated user can bypass configured WebAuthn policies during credential registration by manipulating client-side JavaScript. This occurs because the server-side processAction() fails to validate that the newly created credential's parameters, such as public key algorithms, match the realm's configured WebAuthn policies. This could lead to the creation of credentials that do not adhere to administrative security requirements, potentially weakening the overall security posture of the system by allowing non-compliant authentication methods.
Vulnerability Analysis
CVE-2026-8830 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 1 day later.
Weakness Type
Use of Client-Side Authentication
A client/server product performs authentication within client code but not in server code, allowing server-side authentication to be bypassed via a modified client that omits the authentication check. Client-side authentication is extremely weak and may be breached easily. Any attacker may read the source code and reverse-engineer the authentication mechanism to access parts of the application which would otherwise be protected.
Products Associated with CVE-2026-8830
Want to know whenever a new CVE is published for Red Hat Build Keycloak? stack.watch will email you.
