Description
A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.
Published: 2026-04-02
Score: 8.1 High
EPSS: < 1% Very Low
KEV: No
Impact: Unauthorized Access to User Resources
Action: Immediate Patch
AI Analysis

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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-f2hx-5fx3-hmcv Keycloak: UMA Policy Resource Injection Allows Unauthorized Cross-User Permission Grants
History

Thu, 16 Apr 2026 21:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:*

Fri, 03 Apr 2026 01:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 02 Apr 2026 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
CPEs cpe:/a:redhat:build_keycloak:26.2::el9
Vendors & Products Redhat build Of Keycloak
References

Thu, 02 Apr 2026 14:15:00 +0000

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

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


Thu, 02 Apr 2026 13:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.
Title Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-551
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}


Subscriptions

Redhat Build Keycloak Build Of Keycloak
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-04-02T16:35:04.681Z

Reserved: 2026-03-23T08:51:40.787Z

Link: CVE-2026-4636

cve-icon Vulnrichment

Updated: 2026-04-02T13:13:51.299Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-02T13:16:27.210

Modified: 2026-04-16T20:50:00.623

Link: CVE-2026-4636

cve-icon Redhat

Severity : Important

Publid Date: 2026-04-02T12:30:00Z

Links: CVE-2026-4636 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-03T09:18:46Z

Weaknesses