CVE-2026-37979

Keycloak: keycloak: information disclosure via oidc token introspection endpoint audience bypass

Published May 19, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-4x37-hw65-52w8 Keycloak: Information disclosure via OIDC token introspection endpoint audience bypass
History
Type Values Removed Values Added
Weaknesses CWE-200
Type Values Removed Values Added
Weaknesses CWE-639
Type Values Removed Values Added
CPEs cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*
Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.4::el9
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Vendors & Products Redhat build Of Keycloak
Type Values Removed Values Added
Weaknesses CWE-200
CWE-284
Type Values Removed Values Added
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.
Title Keycloak: keycloak: information disclosure via oidc token introspection endpoint audience bypass
First Time appeared Redhat
Redhat build Keycloak
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Oct 29, 2026, 9:29 AM
Reserved
Apr 6, 2026, 7:48 AM
Status
Modified
Published
May 19, 2026, 12:16 PM
Modified
Oct 29, 2026, 10:17 AM
Severity
Moderate
Public date
May 19, 2026, 12:00 AM