Android intent URLs given to Firefox for Android can be used to navigate from HTTP or HTTPS URLs to local "file:" URLs, allowing for the reading of local data through a violation of same-origin policy. Note: This attack only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 54.
https://www.mozilla.org/security/advisories/mfsa2017-15/
https://bugzilla.mozilla.org/show_bug.cgi?id=1356893