Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Redhat | Build Of Keycloak | - |
| Redhat | Data Grid | 8.0 |
| Redhat | Jboss Enterprise Application Platform Expansion Pack | - |
| Redhat | Single Sign-On | 7.0 |
Related Weaknesses (CWE)
References
- https://access.redhat.com/security/cve/CVE-2026-16093Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2501729Issue TrackingVendor Advisory
FAQ
What is CVE-2026-16093?
CVE-2026-16093 is a vulnerability with a CVSS score of 5.4 (MEDIUM). 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 enforce...
How severe is CVE-2026-16093?
CVE-2026-16093 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-16093?
Check the references section above for vendor advisories and patch information. Affected products include: Redhat Build Of Keycloak, Redhat Data Grid, Redhat Jboss Enterprise Application Platform Expansion Pack, Redhat Single Sign-On.