The kernel in Apple OS X before 10.10.2 does not properly perform identitysvc validation of certain directory-service functionality, which allows local users to gain privileges or spoof directory-service responses via unspecified vectors.
https://exchange.xforce.ibmcloud.com/vulnerabilities/100517
http://www.securitytracker.com/id/1031650
http://support.apple.com/HT204244
http://lists.apple.com/archives/security-announce/2015/Jan/msg00003.html