CVE-2026-9099: Red Hat Build Of Keycloak

High severity, CVSS 7.7. EPSS: 0.5% chance of exploitation in the next 30 days.

A flaw was found in Keycloak. A missing authorization check in the GroupResource.addChild() endpoint within the Admin REST API allows an authenticated user with limited administrative privileges to reparent any existing group. When Fine-Grained Admin Permissions v2 (FGAPv2) is enabled, an attacker with management rights over a single low-privilege group can reparent a highly privileged group (such as one possessing the realm-admin role) under their managed group. Because group permissions follow a hierarchical structure, this action unauthorizedly grants the attacker management and password-reset capabilities over the members of the targeted privileged group. An attacker can exploit this to reset an administrator's password, compromise the account, and achieve a full realm takeover, leading to a complete compromise of confidentiality, integrity, and availability.

Affected products

• Red Hat Build Of Keycloak: from 26.4, before 26.4.13 (fixed in 26.4.13); from 26.6, before 26.6.4 (fixed in 26.6.4)

Published 2026-06-25. Last modified 2026-07-15.