Keycloak TokenManager Stateless Token Validation Bypass
CVE-2026-96447 Published on November 6, 2026
Keycloak-services: keycloak-services: stateless token preferred_username fallback enables identity rebinding
A flaw was found in the TokenManager component of Keycloak, an open-source identity and access management solution. The issue occurs during the validation of stateless access tokens when the original user ID no longer exists. Keycloak incorrectly falls back to using the username to identify the user without verifying if the identity matches the original token subject. This could allow an attacker with an old token to gain access to a newly created service account if it shares the same client ID as a previously deleted one.
Vulnerability Analysis
CVE-2026-96447 can be exploited with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 44 days later.
Weakness Type
What is an authentification Vulnerability?
When an actor claims to have a given identity, the software does not prove or insufficiently proves that the claim is correct.
CVE-2026-96447 has been classified to as an authentification vulnerability or weakness.
Products Associated with CVE-2026-96447
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