Org.keycloak.protocol.oidc.endpoints.logoutendpoint: offline session takeover due to reused authentication session id
Vulnerability Description
A flaw was found in Keycloak. In Keycloak where a user can accidentally get access to another user's session if both use the same device and browser. This happens because Keycloak sometimes reuses session identifiers and doesn’t clean up properly during logout when browser cookies are missing. As a result, one user may receive tokens that belong to another user.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
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Credits & Attribution
The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:
- Red Hat would like to thank Simon Levermann (CTS EVENTIM Solutions GmbH) for reporting this issue.
References
- https://access.redhat.com/errata/RHSA-2025:21370
- https://access.redhat.com/errata/RHSA-2025:21371
- https://access.redhat.com/errata/RHSA-2025:22088
- https://access.redhat.com/errata/RHSA-2025:22089
- https://access.redhat.com/security/cve/CVE-2025-12390
- https://bugzilla.redhat.com/show_bug.cgi?id=2406793
- https://github.com/keycloak/keycloak/issues/43853
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