The Firewall component in Apple OS X Server before 4.1 uses an incorrect pathname in configuration files, which allows remote attackers to bypass network-access restrictions by sending packets for which custom-rule blocking was intended.
https://support.apple.com/HT204201
http://www.securitytracker.com/id/1032197
http://lists.apple.com/archives/security-announce/2015/Apr/msg00006.html