mar_read.c in the Updater in Mozilla Firefox before 40.0 and Firefox ESR 38.x before 38.2 allows local users to gain privileges or cause a denial of service (out-of-bounds write) via a crafted name of a Mozilla Archive (aka MAR) file.
https://security.gentoo.org/glsa/201605-06
https://bugzilla.mozilla.org/show_bug.cgi?id=1184500
http://www.securitytracker.com/id/1033372
http://www.securitytracker.com/id/1033247
http://www.securityfocus.com/bid/76294
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2015/mfsa2015-85.html
http://lists.opensuse.org/opensuse-updates/2015-08/msg00031.html
http://lists.opensuse.org/opensuse-updates/2015-08/msg00030.html
http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00015.html
http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00014.html