CVE-2026-16093 — Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers
Keycloak 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 discov…
Published: 2026-07-17 · CVSS: 5.4 · CVSS 3.1
Keycloak 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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7