Race condition in LoginWindow in Apple OS X before 10.10 allows physically proximate attackers to obtain access by leveraging an unattended workstation on which screen locking had been attempted.
https://support.apple.com/kb/HT6535
https://exchange.xforce.ibmcloud.com/vulnerabilities/97630
http://www.securitytracker.com/id/1031063
http://www.securityfocus.com/bid/70622
http://archives.neohapsis.com/archives/bugtraq/2014-10/0101.html