23 Oct 2026 15:48:27 UTC
Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers
cve-program · CVE-2026-16093 · Published
CVE-2026-16093
Red Hat build of Keycloak 26.6 · Vulnerability
CVSS 3.1 5.4 MEDIUMCheck source for fixed versionsKEV status unknown
cve-program · CVE-2026-16093
PublishedKeycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows the attacker to authenticate using simpler methods like a client secret even when the administrator has mandated more secure, signed assertions.
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