See https://www.mozilla.org/en-US/firefox/49.0.2/releasenotes/ and https://www.mozilla.org/en-US/security/advisories/mfsa2016-87/ Fixes MFSA-2016-87: - CVE-2016-5287 / bugzil.la/1309823 - CVE-2016-5288 / bugzil.la/1310183 (bug information private) prodded by naddy@