Description
A flaw was found in Keycloak. This access control vulnerability in Keycloak's OpenID Connect (OIDC) token introspection endpoint allows a confidential client to bypass audience restrictions. An attacker-controlled client with valid credentials can retrieve sensitive token claims intended for other resource servers, compromising the confidentiality of lightweight access tokens. This issue can be exploited remotely by any confidential client in the realm with valid credentials.
Affected products
redhat: build of keycloak
References4
- access.redhat.com/errata/RHSA-2026:19596 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:19597 Vendor Advisory
- access.redhat.com/security/cve/CVE-2026-37979 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2455328 Vendor Advisory
Metrics
- CVSS 3.1
-
6.5
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 31 · as of 14 November 2026
- CWE
- CWE-639CWE-284
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.