The kernel in Apple iOS before 9.2, OS X before 10.11.2, tvOS before 9.1, and watchOS before 2.1 allows local users to gain privileges via a crafted mach message that is misparsed.
https://www.exploit-db.com/exploits/39375/
https://www.exploit-db.com/exploits/39374/
https://www.exploit-db.com/exploits/39373/
https://www.exploit-db.com/exploits/39371/
https://support.apple.com/HT205641
https://support.apple.com/HT205640
https://support.apple.com/HT205637
https://support.apple.com/HT205635
http://www.securitytracker.com/id/1034344
http://www.securityfocus.com/bid/78719
http://lists.apple.com/archives/security-announce/2015/Dec/msg00005.html
http://lists.apple.com/archives/security-announce/2015/Dec/msg00002.html
http://lists.apple.com/archives/security-announce/2015/Dec/msg00001.html
http://lists.apple.com/archives/security-announce/2015/Dec/msg00000.html