Mozilla Foundation Security Advisory 2010-43
Title: Same-origin bypass using canvas context
Announced: July 20, 2010
Reporter: Vladimir Vukicevic
Products: Firefox, Thunderbird
Fixed in: Firefox 3.6.7
Mozilla developer Vladimir Vukicevic reported that a canvas element can be used to read data from another site, violating the same-origin policy. The read restriction placed on a canvas element which has had cross-origin data rendered into it can be bypassed by retaining a reference to the canvas element's context and deleting the associated canvas node from the DOM.