As per upstream advisory:
The (poorly named) dnsserver RPC pipe provides administrative facilities to modify DNS records and zones.
Samba, when acting as an AD DC, stores DNS records in LDAP.
In AD, the default permissions on the DNS partition allow creation of new records by authenticated users. This is used for example to allow machines to self-register in DNS.
If a DNS record was created that case-insensitively matched the name of the zone, the ldb_qsort() and dns_name_compare() routines could be confused into reading memory prior to the list of DNS entries when responding to DnssrvEnumRecords() or DnssrvEnumRecords2() and so following invalid memory as a pointer.
Name: the Samba project
Upstream: Andreas Oster
The dnsserver task can be stopped by setting
'dcerpc endpoint servers = -dnsserver'
in the smb.conf and restarting Samba.
This flaw does not affect the version of samba shipped with Red Hat Enterprise Linux because there is no support for samba as Active Directory Domain Controller.
Created samba tracking bugs for this issue:
Affects: fedora-all [bug 1781542]
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):