As per samba upstream advisory:
Samba, operating as an AD DC, is sometimes operated in a domain with a mix of Samba and Windows Active Directory Domain Controllers.
All versions of Samba from 4.0.0 to 4.3.2 inclusive, when deployed as an AD DC in the same domain with Windows DCs, could be used to override the protection against the MS15-096 / CVE-2015-2535 security issue in Windows.
Prior to MS16-096 it was possible to bypass the quota of machine accounts a non-administrative user could create. Pure Samba domains are not impacted, as Samba does not implement the SeMachineAccountPrivilege functionality to allow non-administrator users to create new computer objects.
The following mitigation was suggested by upstream:
Only users with SeMachineAccountPrivilege can exploit this issue in Windows, removing this privilege from "Authenticated Users" can provide a mitigation.
Red Hat would like to thank the Samba project for reporting this issue. Upstream cknowledges Andrew Bartlett of the Samba Team and Catalyst as the original reporters.