CVE 2014-5195
Unity before 7.2.3 and 7.3.x before 7.3.1, as used in Ubuntu, does not properly take focus of the keyboard when switching to the lock screen, which allows physically proximate attackers to bypass the lock screen by (1) leveraging a machine that had text selected when locking or (2) resuming from a suspension.
See the 
CVE page on Mitre.org
for more details.
