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Low · 3.7 CVE-2026-18206 EUVD-2026-51486GHSA-2w88-g477-cxmj

Keycloak-services: keycloak-services: client policy source-host wildcard domain matching bypass

Published Jul 31, 2026 · Updated Nov 7, 2026 · Assigned by redhat

Description

A flaw was found in the keycloak-services component of Keycloak, which provides identity and access management services. The issue occurs when a realm administrator uses a wildcard domain (like *.example.com) to restrict which hosts can register or update clients. Due to improper validation, the system accepts any hostname that ends with the specified domain suffix, even if it is not a legitimate subdomain. An attacker who can control the reverse DNS of their connection can bypass these host-based restrictions, potentially allowing unauthorized client modifications.

Affected products

VendorProductAffectedFixed
Red Hat Red Hat build of Keycloak 26.6 — —
Red Hat Red Hat build of Keycloak 26.6.8 — —
Red Hat Red Hat Data Grid 8 — —
Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack — —
Red Hat Red Hat Single Sign-On 7 — —

Advisories 1

References