CVE 2012-0460
Mozilla Firefox 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8 do not properly restrict write access to the window.fullScreen object, which allows remote attackers to spoof the user interface via a crafted web page.
See the 
CVE page on Mitre.org
for more details.
