The mach_vm_read functionality in the kernel in Apple OS X before 10.10.3 allows local users to cause a denial of service (system crash) via unspecified vectors.
https://support.apple.com/HT204659
http://www.securitytracker.com/id/1032048
http://www.securityfocus.com/bid/73982
http://lists.apple.com/archives/security-announce/2015/Apr/msg00001.html