The add-on installation feature in Mozilla Firefox before 40.0.3 and Firefox ESR 38.x before 38.2.1 allows remote attackers to bypass an intended user-confirmation requirement by constructing a crafted data: URL and triggering navigation to an arbitrary http: or https: URL at a certain early point in the installation process.
lists.opensuse.org/opensuse-security-announce/2015-09/msg00013.html
lists.opensuse.org/opensuse-security-announce/2015-11/msg00025.html
lists.opensuse.org/opensuse-updates/2015-09/msg00000.html
rhn.redhat.com/errata/RHSA-2015-1693.html
www.debian.org/security/2015/dsa-3345
www.mozilla.org/security/announce/2015/mfsa2015-95.html
www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
www.securityfocus.com/bid/76505
www.securitytracker.com/id/1033396
www.ubuntu.com/usn/USN-2723-1
bugzilla.mozilla.org/show_bug.cgi?id=1042699