The Application Firewall in Apple Mac OS X 10.5, when "Block all incoming connections" is enabled, does not prevent root processes or mDNSResponder from accepting connections, which might allow remote attackers or local root processes to bypass intended access restrictions.
https://exchange.xforce.ibmcloud.com/vulnerabilities/38506
http://www.vupen.com/english/advisories/2007/3897
http://www.securityfocus.com/bid/26461
http://securitytracker.com/id?1018958
http://secunia.com/advisories/27695
http://lists.apple.com/archives/security-announce/2007/Nov/msg00004.html