CVE 2011-2986
Mozilla Firefox 4.x through 5, Thunderbird before 6, SeaMonkey 2.x before 2.3, and possibly other products, when the Direct2D (aka D2D) API is used on Windows, allows remote attackers to bypass the Same Origin Policy, and obtain sensitive image data from a different domain, by inserting this data into a canvas.
See the
CVE page on Mitre.org
for more details.