The WebGL implementation in Mozilla Firefox before 24.0, when NVIDIA graphics drivers are used on Mac OS X, allows remote attackers to obtain desktop-screenshot data by reading from a CANVAS element.
https://bugzilla.mozilla.org/show_bug.cgi?id=879656
http://www.mozilla.org/security/announce/2013/mfsa2013-86.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-September/117526.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-September/116610.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-September/115907.html