Keycloak-services: keycloak-services: client policy source-host wildcard domain matching bypass
This low-severity Red Hat Linux advisory covers CVE-2026-18206 affecting Red Hat Build of Keycloak.
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Summary
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 product named by the advisory: Red Hat Build of Keycloak.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- The issue occurs when a realm administrator uses a wildcard domain (like *.example.com) to restrict which hosts can register or update clients.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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