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OpenAdvisories
High · 8.1 CVE-2026-4636 BIT-keycloak-2026-4636EUVD-2026-18213GHSA-f2hx-5fx3-hmcv

Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.

Published Apr 2, 2026 · Updated Jul 15, 2026 · Assigned by redhat

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

VendorProductAffectedFixed
Red Hat Red Hat build of Keycloak 26.2 — —
Red Hat Red Hat build of Keycloak 26.2.15 — —
Red Hat Red Hat build of Keycloak 26.4 — —
Red Hat Red Hat build of Keycloak 26.4.11 — —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling keycloak-26.4-iamguarded-compat No fix yet —
Wolfi rolling keycloak-26.5 +1 26.5.7-r0 —

Affected packages

EcosystemPackageAffectedFixedRecord
Maven org.keycloak:keycloak-services < 26.5.7 26.5.7 GHSA-f2hx-5fx3-hmcv

Advisories 1

References