LoginWindow in Apple OS X before 10.10.2 does not transition to the lock-screen state immediately upon being woken from sleep, which allows physically proximate attackers to obtain sensitive information by reading the screen.
https://exchange.xforce.ibmcloud.com/vulnerabilities/100521
http://www.securitytracker.com/id/1031650
http://support.apple.com/HT204244
http://lists.apple.com/archives/security-announce/2015/Jan/msg00003.html