Description
A flaw was found in the SAML broker component of Keycloak, which is used to manage identity federation and user authentication. The issue occurs because the IdP-initiated Single Sign-On endpoint fails to check if a provider is restricted to account linking only. This allows an attacker with control over a linked upstream identity to bypass login restrictions and gain full access to a local user account.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 | — | — |
| Red Hat | Red Hat build of Keycloak 26.4.14 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6.5 | — | — |
| 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-2026-2677 RedHat Build of Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 5, 2026
References
- RHSA-2026:50846 vendor-advisory
- RHSA-2026:50847 vendor-advisory
- RHSA-2026:50848 vendor-advisory
- RHSA-2026:50849 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-16442 vdb-entry
- RHBZ#2503138 issue-tracking