CVE-2026-4636
Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.
- State
- Published
- Severity
- 8.1 High
- Published
- Apr 2, 2026
- Updated
- Jul 15, 2026
- Reserved
- Mar 23, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.1 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | redhat |
| 3.1 | 8.1 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | redhat-SADP |
Weaknesses
- CWE-551 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Affected Products
| Product | Versions |
|---|---|
Red Hat build of Keycloak 26.2Red Hat |
|
Red Hat build of Keycloak 26.2Red Hat |
|
Red Hat build of Keycloak 26.2Red Hat |
|
Red Hat build of Keycloak 26.2.15Red Hat | |
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4.11Red Hat |
References
- RHSA-2026:6475vendor-advisory
- RHSA-2026:6476vendor-advisory
- RHSA-2026:6477vendor-advisory
- RHSA-2026:6478vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-4636vdb-entry
- RHBZ#2450251issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4636.json
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