CVE-2026-16093: Reliance on Untrusted Inputs in a Security Decision in Red Hat Red Hat Build of Keycloak
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.
CVE-2026-16093: Reliance on Untrusted Inputs in a Security Decision in Red Hat Red Hat Build of Keycloak
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 v3.1
Score 5.4medium
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-07-17T14:08:34.722Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-16093","vendor":"Red Hat"}]
Threat ID: 6a5b5eba2d1edb114c7fb77f
Added to database: 07/18/2026, 11:08:42 UTC
Last updated: 07/18/2026, 11:08:50 UTC
Views: 2
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