CVE-2026-4636

Name: CVE-2026-4636
Creator: NVD / NIST
Published: 2026-04-02T13:16:27.21+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 0.34%

Last modified Jun 17, 2026

CVE-2026-4636 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. EPSS estimates a 0.34% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

0.34%

25.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-551

Affected Software

Vendor	Product	Versions
Redhat	Build Of Keycloak	All versions
Redhat	Build Of Keycloak	26.2
Redhat	Build Of Keycloak	26.2.15
Redhat	Build Of Keycloak	26.4
Redhat	Build Of Keycloak	26.4.11

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=2450251Exploit, Issue Tracking, Vendor Advisory

Timeline

Published: Apr 2, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-4636?

How severe is CVE-2026-4636?

CVE-2026-4636 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4636?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-4636?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST