TelephonyUI Framework in Apple iOS 7 before 7.1, when Safari is used, does not require user confirmation for FaceTime audio calls, which allows remote attackers to obtain telephone number or e-mail address information via a facetime-audio: URL.
http://www.securityfocus.com/bid/66108
http://support.apple.com/kb/HT6441
http://support.apple.com/kb/HT6162
http://seclists.org/fulldisclosure/2014/Mar/92
http://seclists.org/bugtraq/2014/Mar/63
http://archives.neohapsis.com/archives/bugtraq/2014-09/0106.html