CCrypt in corecrypto in CommonCrypto in Apple iOS before 10 and OS X before 10.12 allows attackers to discover cleartext information by leveraging a function call that specifies the same buffer for input and output.
https://support.apple.com/HT207170
https://support.apple.com/HT207143
http://www.securitytracker.com/id/1036858
http://www.securityfocus.com/bid/93056
http://lists.apple.com/archives/security-announce/2016/Sep/msg00008.html
http://lists.apple.com/archives/security-announce/2016/Sep/msg00006.html