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.
Published: 2026-05-19
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

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

Sign in to view the affected projects.

Advisories
Source ID Title
Github GHSA Github GHSA GHSA-4x37-hw65-52w8 Keycloak: Information disclosure via OIDC token introspection endpoint audience bypass
History

Wed, 03 Jun 2026 20:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*

Wed, 20 May 2026 16:45:00 +0000

Type Values Removed Values Added
References

Wed, 20 May 2026 12:15:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.4::el9
References

Tue, 19 May 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Tue, 19 May 2026 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Vendors & Products Redhat build Of Keycloak

Tue, 19 May 2026 12:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-284

Tue, 19 May 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Tue, 19 May 2026 11:30:00 +0000

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'}


Subscriptions

Redhat Build Keycloak Build Of Keycloak
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-05-20T16:08:52.747Z

Reserved: 2026-04-06T07:48:39.722Z

Link: CVE-2026-37979

cve-icon Vulnrichment

Updated: 2026-05-19T13:40:04.125Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-19T12:16:18.330

Modified: 2026-06-17T10:41:39.593

Link: CVE-2026-37979

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-05-19T00:00:00Z

Links: CVE-2026-37979 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-19T14:30:06Z

Weaknesses