The ArrayBufferBuilder::append function in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x before 38.1, and Thunderbird before 38.1 accesses unintended memory locations, which has unspecified impact and attack vectors.
https://security.gentoo.org/glsa/201512-10
https://bugzilla.mozilla.org/show_bug.cgi?id=1168207
http://www.ubuntu.com/usn/USN-2673-1
http://www.ubuntu.com/usn/USN-2656-2
http://www.ubuntu.com/usn/USN-2656-1
http://www.securitytracker.com/id/1032784
http://www.securitytracker.com/id/1032783
http://www.securityfocus.com/bid/75541
http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2015/mfsa2015-66.html
http://www.debian.org/security/2015/dsa-3324
http://www.debian.org/security/2015/dsa-3300
http://rhn.redhat.com/errata/RHSA-2015-1455.html
http://rhn.redhat.com/errata/RHSA-2015-1207.html
http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00021.html
http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00034.html
http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00033.html
http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00031.html
http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00025.html