CVE-2026-4636

Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.

Published Apr 2, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
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.

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
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:*:*:*
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
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'}

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Jul 15, 2026, 12:50 AM
Reserved
Mar 23, 2026, 8:51 AM
Status
Modified
Published
Apr 2, 2026, 1:16 PM
Modified
Oct 26, 2026, 9:10 PM
Severity
Important
Public date
Apr 2, 2026, 12:30 PM