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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 6
https://access.redhat.com/security/cve/CVE-2026-16442
secalert@redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2503138
secalert@redhat.com
https://access.redhat.com/errata/RHSA-2026:50846
secalert@redhat.com
https://access.redhat.com/errata/RHSA-2026:50847
secalert@redhat.com
https://access.redhat.com/errata/RHSA-2026:50848
secalert@redhat.com
https://access.redhat.com/errata/RHSA-2026:50849
secalert@redhat.com