CVE-2025-12390 Org.keycloak.protocol.oidc.endpoints.logoutendpoint: offline session takeover due to reused authentication session id
Attackers can hijack user sessions by exploiting reused authentication session IDs during logout, leading to unauthorized access to another user's account.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-12390?
CVE-2025-12390 is a medium-severity authentication bypass vulnerability in Red Hat build of Keycloak 26.2, published on 28 Oct 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-384
Which versions are affected by CVE-2025-12390?
2 open source packages ship an affected version, including org.keycloak:keycloak-services.
| Package | Affected | Fixed in |
|---|---|---|
org.keycloak:keycloak-services Maven | All versions | 26.0.0 |
org.keycloak:keycloak-services Maven | All versions | 26.0.0 |
How do I fix CVE-2025-12390?
Upgrade org.keycloak:keycloak-services to 26.0.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-12390 being exploited?
There is no known exploitation of CVE-2025-12390 in the wild and no public exploit code.
Sources
Also known as ECHO-c70d-0dfc-e7d7, GHSA-rg35-5v25-mqvp, MINI-3mx9-5g5m-mf9x, MINI-r2p7-f2gx-7gh6.