CVE-2026-18206: Red Hat Build Of Keycloak

Low severity, CVSS 3.7. EPSS: 0.3% chance of exploitation in the next 30 days.

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

• Red Hat Build Of Keycloak: affected versions not specified

Published 2026-07-31. Last modified 2026-08-07.