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Vulnerability · Published Oct 28, 2025 · Assigned by redhat

CVE-2025-12390Org.keycloak.protocol.oidc.endpoints.logoutendpoint: offline session takeover due to reused authentication session id

Medium 6.0

In plain English

A medium-severity session fixation in keycloak from Keycloak. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.0Medium
Exploit odds (30 days)0.1%top 96.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Mavenorg.keycloak:keycloak-services26.0.0GHSA-rg35-5v25-mqvp

Affected products (as reported)

VendorProductVersions
Keycloak keycloak 0 – before 26.0.0
Red Hat Red Hat build of Keycloak 26.2 see references
Red Hat Red Hat build of Keycloak 26.2 see references
Red Hat Red Hat build of Keycloak 26.2 see references
Red Hat Red Hat build of Keycloak 26.2.11 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4.4 see references

Weakness: CWE-384 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

References