Review reviewHigh

CVE-2026-4636

Red Hat Red Hat build of Keycloak 26.2, Red Hat build of Keycloak 26.2.15, Red Hat build of Keycloak 26.4

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.

CVSS
8.1
EPSS
0.35%
27.3% percentile
CISA KEV
Not listed
Published
2026.04.02
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.35%
Technical severityCVSS 8.1

Vulnerability overview

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.

Affected product and versions

Product
Red Hat Red Hat build of Keycloak 26.2, Red Hat build of Keycloak 26.2.15, Red Hat build of Keycloak 26.4
Affected versions
26.2, 26.2.15, 26.4, 26.4.11
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Red Hat Red Hat build of Keycloak 26.2, Red Hat build of Keycloak 26.2.15, Red Hat build of Keycloak 26.4 and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CWE
CWE-551