WebKit in Apple iOS before 9 allows remote attackers to trigger a dialing action via a crafted (1) tel://, (2) facetime://, or (3) facetime-audio:// URL.
http://lists.apple.com/archives/security-announce/2015/Sep/msg00001.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00007.html
http://www.securityfocus.com/bid/76766
http://www.securitytracker.com/id/1033609