Keycloak OIDC Logout Session Fixation via Unvalidated Token Hint
CVE-2026-107124 Published on November 6, 2026
Keycloak-services: keycloak-services: oidc logout endpoint session fixation via id_token_hint leading to account takeover
A flaw was found in the OIDC logout endpoint of the keycloak-services component, which handles user session termination in Red Hat Build of Keycloak. The issue occurs because the system sets a session cookie based on an unvalidated token hint before completing security checks. An attacker can use this flaw to fix a session ID in a victim's browser, allowing them to hijack the victim's subsequent login and gain full control over their account.
Vulnerability Analysis
CVE-2026-107124 is exploitable with network access, requires user interaction and a 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 high impact on confidentiality and integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 30 days later.
Weakness Type
Session Fixation
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
Products Associated with CVE-2026-107124
stack.watch emails you whenever new vulnerabilities are published in Red Hat Build Keycloak or Red Hat Single Sign On. Just hit a watch button to start following.
