Canvas allows the use of the feDisplacementMap filter on images loaded cross-origin. The rendering by the filter is variable depending on the input pixel, allowing for timing attacks when the images are loaded from third party locations. External Reference: https://www.mozilla.org/security/announce/2016/mfsa2016-89.html Acknowledgements: Name: the Mozilla project Upstream: Markus Stange Statement: This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5, 6 and 7.