Race condition in kext tools in Apple OS X before 10.10.4 allows local users to bypass intended signature requirements for kernel extensions by leveraging improper pathname validation.
http://www.securitytracker.com/id/1032760
http://www.securityfocus.com/bid/75493
http://support.apple.com/kb/HT204942
http://lists.apple.com/archives/security-announce/2015/Jun/msg00002.html