The internal DNS server in Samba 4.x before 4.0.18 does not check the QR field in the header section of an incoming DNS message before sending a response, which allows remote attackers to cause a denial of service (CPU and bandwidth consumption) via a forged response packet that triggers a communication loop, a related issue to CVE-1999-0103.
http://www.securitytracker.com/id/1030309
http://www.securityfocus.com/bid/67691
http://www.samba.org/samba/security/CVE-2014-0239