# CVE-2026-4636

## Summary

- **CVE ID:** CVE-2026-4636
- **Severity:** HIGH
- **CVSS Score:** 8.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N)
- **CWE:** CWE-551
- **Published:** Apr 2, 2026
- **Last Modified:** Jul 15, 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.

## Affected Products

- Red Hat — Red Hat build of Keycloak 26.2 (26.2.15-1)
- Red Hat — Red Hat build of Keycloak 26.2 (26.2-18)
- Red Hat — Red Hat build of Keycloak 26.4 (26.4.11-1)
- Red Hat — Red Hat build of Keycloak 26.4 (26.4-14)

## References

- [CNA](https://access.redhat.com/errata/RHSA-2026:6475)
- [CNA](https://access.redhat.com/errata/RHSA-2026:6476)
- [CNA](https://access.redhat.com/errata/RHSA-2026:6477)
- [CNA](https://access.redhat.com/errata/RHSA-2026:6478)
- [CNA](https://access.redhat.com/security/cve/CVE-2026-4636)
- [CNA](https://bugzilla.redhat.com/show_bug.cgi?id=2450251)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4636.json)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.35%
- **EPSS Percentile:** 28.1

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._