Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-08-05T02:02:00 keycloak-services: keycloak-services: SAML IdP-initiated broker login bypasses link-only restriction 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N CWE-346

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.

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.

The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that it allows for an authentication bypass. Successful exploitation allows an attacker to obtain a full authenticated session as a linked local user, bypassing administrative restrictions. The vulnerability's root cause is the lack of enforcement of the link-only configuration within the SAML IdP-initiated SSO endpoint. Red Hat would like to thank Paul Bottinelli (Trail of Bits) for reporting this issue. Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Red Hat build of Keycloak 26.4 2026-08-05T00:00:00Z RHSA-2026:50847 rhbk/keycloak-operator-bundle:26.4.14-1 Red Hat build of Keycloak 26.4 2026-08-05T00:00:00Z RHSA-2026:50847 rhbk/keycloak-rhel9:26.4-22 Red Hat build of Keycloak 26.4 2026-08-05T00:00:00Z RHSA-2026:50847 rhbk/keycloak-rhel9-operator:26.4-22 Red Hat build of Keycloak 26.4.14 2026-08-05T00:00:00Z RHSA-2026:50846 keycloak-services Red Hat build of Keycloak 26.4.14 2026-08-05T00:00:00Z RHSA-2026:50846 rhbk-openshift-rhel9/rhbk-openshift-rhel9 Red Hat build of Keycloak 26.6 2026-08-05T00:00:00Z RHSA-2026:50849 rhbk/keycloak-operator-bundle:26.6.5-1 Red Hat build of Keycloak 26.6 2026-08-05T00:00:00Z RHSA-2026:50849 rhbk/keycloak-rhel9:26.6-11 Red Hat build of Keycloak 26.6 2026-08-05T00:00:00Z RHSA-2026:50849 rhbk/keycloak-rhel9-operator:26.6-11 Red Hat build of Keycloak 26.6.5 2026-08-05T00:00:00Z RHSA-2026:50848 keycloak-services Red Hat build of Keycloak 26.6.5 2026-08-05T00:00:00Z RHSA-2026:50848 rhbk-keycloak-rhel9/rhbk-keycloak-rhel9 Red Hat build of Keycloak 26.6.5 2026-08-05T00:00:00Z RHSA-2026:50848 rhbk-openshift-rhel9/rhbk-openshift-rhel9 Red Hat Data Grid 8 Not affected keycloak-services Red Hat JBoss Enterprise Application Platform Expansion Pack Not affected keycloak-services Red Hat Single Sign-On 7 Not affected keycloak-services https://www.cve.org/CVERecord?id=CVE-2026-16442 https://nvd.nist.gov/vuln/detail/CVE-2026-16442