Session fixation in Keycloak - CVE-2025-12390
Published: November 18, 2025
Vulnerability identifier: #VU118575
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:U/U:Clear
CVE-ID: CVE-2025-12390
CWE-ID: CWE-384
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Keycloak
Affected software:
Keycloak
Keycloak
Detailed vulnerability description
The vulnerability allows a local user to gain access to another session.
The vulnerability exists due to accidental session identifier reuse when logging in on the same device. A local user can get access to another user's session if both use the same device and browser.
How to mitigate CVE-2025-12390
Install updates from vendor's website.