Google security researcher Michal Zalewski reported that when a malformed bitmap image is rendered by the bitmap decoder within a <canvas> element, memory may not always be properly initialized. The resulting image then uses this uninitialized memory during rendering, allowing data to potentially leak to web content. 


External Reference:

http://www.mozilla.org/security/announce/2015/mfsa2015-02.html


Acknowledgements:

Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Michal Zalewski as the original reporter.

Statement:

This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5, 6 and 7.