CVE-2026-11861: Freeipa: idm: ipa: freeipa: obtaining tgs with impersonating cname through trust relationships
A flaw was found in FreeIPA. When a trust relationship is configured between FreeIPA and Active Directory, Active Directory users can bypass authentication for FreeIPA services, including the portal, SMB server, and LDAP directory. This is possible by impersonating a client name in the Ticket Granting Service (TGS) due to FreeIPA services not verifying Privilege Attribute Certificate (PAC) certificates. This vulnerability could allow an authenticated Active Directory user to escalate their privileges within the FreeIPA domain.
Other sources
If trust relationship between FreeIPA and Active Directory is configured (established/created), AD users can bypass authentication of the FreeIPA portal, SMB server, LDAP directory and, presumably, any other GSSAPI services unauthorized, using impersonation in TGS, under certain conditions. In the worst case scenario a user could escalate their priveleges (permissions/rights) in FreeIPA domain. This is due to the fact that the portal, like other GSSAPI services, is not configured to verify PAC certificates and trusts the TGS cname field.
— Red Hat
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments with an established trust relationship between FreeIPA and Active Directory are exposed. The affected FreeIPA services include the portal, SMB server, and LDAP directory, and other GSSAPI services may also be affected.
What level of access does an attacker need?
An attacker needs to be an authenticated Active Directory user in an environment where the Active Directory-FreeIPA trust is configured. They can exploit impersonation in Ticket Granting Service requests to bypass authentication for FreeIPA services and potentially escalate privileges in the FreeIPA domain.