The kernel in Apple iOS before 7 allows remote attackers to cause a denial of service (assertion failure and device restart) via an invalid packet fragment.
http://www.securitytracker.com/id/1029054
http://support.apple.com/kb/HT5934
http://secunia.com/advisories/54886
http://lists.apple.com/archives/security-announce/2013/Sep/msg00006.html