CVE-2026-4636 — HIGH (8.1) — White Hats Nepal

Vulnerability 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.

CVSS Score

8.1

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Affected Products

Vendor	Product	Versions
Redhat	Build Of Keycloak	-

Related Weaknesses (CWE)

CWE-551

References

https://access.redhat.com/errata/RHSA-2026:6475Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:6476Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:6477Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:6478Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-4636Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2450251ExploitIssue TrackingVendor Advisory

FAQ

What is CVE-2026-4636?

CVE-2026-4636 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 ...

How severe is CVE-2026-4636?

CVE-2026-4636 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-4636?

Check the references section above for vendor advisories and patch information. Affected products include: Redhat Build Of Keycloak.