The Firefox Health Reports (aka FHR or about:healthreport) feature in Mozilla Firefox before 46.0 does not properly restrict the origin of events, which makes it easier for remote attackers to modify sharing preferences by leveraging access to the remote-report IFRAME element.
lists.opensuse.org/opensuse-security-announce/2016-05/msg00005.html
lists.opensuse.org/opensuse-updates/2016-05/msg00038.html
www.mozilla.org/security/announce/2016/mfsa2016-48.html
www.securitytracker.com/id/1035692
www.ubuntu.com/usn/USN-2936-1
www.ubuntu.com/usn/USN-2936-2
www.ubuntu.com/usn/USN-2936-3
bugzilla.mozilla.org/show_bug.cgi?id=870870
security.gentoo.org/glsa/201701-15