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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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
- WID-SEC-2026-2614 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
References
- RHSA-2026:95761 vendor-advisory
- RHSA-2026:95762 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-18206 vdb-entry
- RHBZ#2508292 issue-tracking