Improper access control in Keycloak - CVE-2026-37979

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Main Vulnerability Database Vulnerabilities #VU148951

Improper access control in Keycloak - CVE-2026-37979

Published: September 10, 2026


Vulnerability identifier: #VU148951
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-37979
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to disclose sensitive token claims.

The vulnerability exists due to improper access control in Keycloak\'s OpenID Connect token introspection endpoint when processing introspection requests from confidential clients. A remote user can use valid confidential-client credentials to bypass audience restrictions and disclose sensitive token claims.

Lightweight access tokens are affected.


Affected software

Keycloak
Red Hat build of Keycloak

How to mitigate CVE-2026-37979

Install security update from vendor's website.

Keycloak - update to 26.6.2
Red Hat build of Keycloak - update to 26.4.12

External References

Related Security Bulletins