Mozilla Firefox before 44.0.2 does not properly restrict the interaction between Service Workers and plugins, which allows remote attackers to bypass the Same Origin Policy via a crafted web site that triggers spoofed responses to requests that use NPAPI, as demonstrated by a request for a crossdomain.xml file.
lists.opensuse.org/opensuse-updates/2016-02/msg00102.html
lists.opensuse.org/opensuse-updates/2016-02/msg00142.html
www.mozilla.org/security/announce/2016/mfsa2016-13.html
www.securitytracker.com/id/1035007
www.ubuntu.com/usn/USN-2893-1
bugzilla.mozilla.org/show_bug.cgi?id=1245724
security.gentoo.org/glsa/201605-06