Login Window in Apple OS X before 10.11.6 does not properly initialize memory, which allows local users to cause a denial of service via unspecified vectors.
https://support.apple.com/HT206903
http://zerodayinitiative.com/advisories/ZDI-16-431/
http://www.securitytracker.com/id/1036348
http://www.securityfocus.com/bid/91824
http://lists.apple.com/archives/security-announce/2016/Jul/msg00000.html