PT-2026-66722 · Red Hat · Red Hat Build Of Keycloak+3

CVE-2026-18203 · Published 2026-07-31 · Updated 2026-07-31

Mitre

CVSS v3.1

6.5

Medium

Base vector

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

A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.

Fix

Incorrect Authorization

Weakness Enumeration

CWE-863

Related Identifiers

CVE-2026-18203

Affected Products

Red Hat Build Of Keycloak

Red Hat Data Grid 8

Red Hat Jboss Enterprise Application Platform Expansion Pack

Red Hat Single Sign-On 7

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-18203 · Security Note
• https://access.redhat.com/security/cve/CVE-2026-18203 · Note
• https://bugzilla.redhat.com/show_bug.cgi?id=2508291 · Note