CVE-2026-4636 HIGH

CVE-2026-4636: Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.

Vendor Red Hat
Product Red Hat build of Keycloak 26.2.15
Weakness CWE-551
Published April 2, 2026
Last update June 30, 2026

CVSS base score

8.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 2, 2026 CVE published
June 30, 2026 Record updated