CVE-2026-15573: Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-08-31
Weakness: CWE-551

Description

A flaw was found in Keycloak's Authorization Services. The component responsible for matching request paths to security policies (PathMatcher) does not properly normalize URIs before comparison. By adding extra characters like a trailing slash or matrix parameters to a URL, an attacker can trick the system into applying a less restrictive security policy than intended. This allows an authenticated user to access administrative or restricted areas they should not have permission to see.

Affected products

Red Hat build of Keycloak 26.4: from 26.4 before 26.4.14; from 26.6 before 26.6.5 — fixed in 26.4.14, 26.6.5
RedHat Data Grid: 8.0
RedHat Jboss Enterprise Application Platform Expansion Pack: all versions
Red Hat Single Sign-On: 7.0

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.4.14, 26.6.5. Check the vendor advisory for mitigations.

References

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