The Sandbox Profiles component in Apple iOS before 10 does not properly restrict access to directory metadata for SMS draft directories, which allows attackers to discover text-message recipients via a crafted app.
https://support.apple.com/HT207143
http://www.securitytracker.com/id/1036797
http://www.securityfocus.com/bid/92932
http://lists.apple.com/archives/security-announce/2016/Sep/msg00008.html
http://lists.apple.com/archives/security-announce/2016/Sep/msg00002.html