Security researcher Abdulrahman Alqabandi reported that when a data: URI is parsed, the hash ('#') symbol is incorrectly handled, allowing for spoofing attacks. This issue could result in the wrong URI being displayed as a location, which can mislead users to believe they are on a different site than the one loaded. External Reference: https://www.mozilla.org/security/announce/2015/mfsa2015-141.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Abdulrahman Alqabandi 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.