The Push Notifications subsystem in Apple iOS before 7 provides the push-notification token to an app without user approval, which allows attackers to obtain sensitive information via an app that employs a crafted push-notification registration process.
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