CVE 2009-1693
WebKit in Apple Safari before 4.0, iPhone OS 1.0 through 2.2.1, and iPhone OS for iPod touch 1.1 through 2.2.1 allows remote attackers to read images from arbitrary web sites via a CANVAS element with an SVG image, related to a "cross-site image capture issue."
See the 
CVE page on Mitre.org
for more details.
