Vulnerability Report

CVE-2026-16093

Title: Client Policy Enforcement Bypass in Keycloak

XSS

Proof Of Concept

No public PoC currently indexed for CVE-2026-16093.

CWE Category CWE-807

Published Date Jul 17, 2026

Modified Date Sep 16, 2026

Exploit Status Not Found

Score 5.4 CVSS v3.1

Exploit Probability (EPSS)

0.39%

Vulnerability Summary

CVE-2026-16093: 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.

Impacted Vendors

redhat 4

pivotal 1

Reference Links

https://access.redhat.com/security/cve/CVE-2026-16093 https://bugzilla.redhat.com/show_bug.cgi?id=2501729

CVSS v3.1

Source Entity [email protected]

Severity MEDIUM

5.4

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns