CVE-2026-4636CWE-551

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

High · published April 2, 2026

CVSS v3.1
8.1
EPSS
0%
Percentile
40.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.1 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00483 · 40.7th percentile
Weakness
CWE-551 · Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Published
2026-04-02T12:45Z
EPSS history
Timeline
  • 02 APR 12:45Z
    Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.
    cvelistv5