The Telephony subsystem in Apple iOS before 9.1 allows attackers to obtain sensitive call-status information via a crafted app.
https://support.apple.com/HT205370
http://www.securitytracker.com/id/1033929
http://www.securityfocus.com/bid/77268
http://lists.apple.com/archives/security-announce/2015/Oct/msg00002.html