A location bar spoofing attack where the location bar of loaded page will be shown over the content of another tab due to a series of JavaScript events combined with fullscreen mode. Note: This issue only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 51.
https://www.mozilla.org/security/advisories/mfsa2017-01/
https://bugzilla.mozilla.org/show_bug.cgi?id=1222798