CVE-2025-12390: Keycloak

Medium severity, CVSS 6.0. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Keycloak Keycloak: before 26.0.0 (fixed in 26.0.0)
• Red Hat Red Hat Build Of Keycloak 26.2: before 26.2.11-1 (fixed in 26.2.11-1); before 26.2-12 (fixed in 26.2-12)
• Red Hat Red Hat Build Of Keycloak 26.2.11
• Red Hat Red Hat Build Of Keycloak 26.4: before 26.4.4-1 (fixed in 26.4.4-1); before 26.4-3 (fixed in 26.4-3)
• Red Hat Red Hat Build Of Keycloak 26.4.4

Published 2025-10-28. Last modified 2026-06-17.