The mach_port_space_info function in osfmk/ipc/mach_debug.c in the XNU kernel in Apple Mac OS X 10.8.x does not initialize a certain structure member, which allows local users to obtain sensitive information from kernel heap memory via a crafted call.
http://www.syscan.org/index.php/sg/program/day/2
http://www.securitytracker.com/id/1029054
http://support.apple.com/kb/HT5934
http://lists.apple.com/archives/security-announce/2013/Sep/msg00006.html