Vulnerability Instance

Security research firm Context IS discovered that
an image from a different domain could be loaded into a WebGL texture,
and then each pixel could be rendered into a canvas element with a
shader program, creating an approximation of the image in a form that
was readable by the creator of the WebGL texture.  This could be used
to steal image data from a different site and is considered a
violation of the same-origin policy.The WebGL functionality was introduced in the browser engine used
by Firefox 4 and SeaMonkey 2.1; the vulnerability does not affect earlier versions.