IOHIDFamily in Apple iOS before 9.1, OS X before 10.11.1, and watchOS before 2.0.1 allows attackers to execute arbitrary code in a privileged context or cause a denial of service (memory corruption) via a crafted app.
https://support.apple.com/HT205378
https://support.apple.com/HT205375
https://support.apple.com/HT205370
http://www.securitytracker.com/id/1033929
http://lists.apple.com/archives/security-announce/2015/Oct/msg00005.html
http://lists.apple.com/archives/security-announce/2015/Oct/msg00003.html
http://lists.apple.com/archives/security-announce/2015/Oct/msg00002.html