Heap-based buffer overflow in the nsCaseTransformTextRunFactory::TransformString function in Mozilla Firefox before 49.0, Firefox ESR 45.x before 45.4, and Thunderbird < 45.4 allows remote attackers to cause a denial of service (boolean out-of-bounds write) or possibly have unspecified other impact via Unicode characters that are mishandled during text conversion.
http://rhn.redhat.com/errata/RHSA-2016-1912.html
https://bugzilla.mozilla.org/show_bug.cgi?id=1291016
https://security.gentoo.org/glsa/201701-15
https://www.mozilla.org/security/advisories/mfsa2016-86/
https://www.mozilla.org/security/advisories/mfsa2016-88/
http://www.debian.org/security/2016/dsa-3674
http://www.mozilla.org/security/announce/2016/mfsa2016-85.html
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html