As per upstream advisory:
The dnsserver RPC pipe provides administrative facilities to modify DNS records and zones which allows an authenticated user to crash the RPC server process via a NULL pointer de-reference. This issue affects Samba 4.0 and later.
There is no further vulnerability associated with this issue, merely a denial of service.
Name: The samba project
The dnsserver task can be stopped by setting
'dcerpc endpoint servers = -dnsserver'
in the smb.conf and restarting Samba.
Upstream bug: https://bugzilla.samba.org/show_bug.cgi?id=13922
Created samba tracking bugs for this issue:
Affects: fedora-all [bug 1721872]
This issue did not affect the version of samba as shipped with 'Red Hat Gluster Storage 3' as they did not include support for Active Directory Domain Controller.