The NVIDIA graphics driver in Apple OS X before 10.10.3 allows local users to gain privileges or cause a denial of service (NULL pointer dereference) via an unspecified IOService userclient type.
https://support.apple.com/HT204659
http://www.securitytracker.com/id/1032048
http://lists.apple.com/archives/security-announce/2015/Apr/msg00001.html