The update implementation in Mozilla Firefox before 38.0 on Windows does not ensure that the pathname for updater.exe corresponds to the application directory, which might allow local users to gain privileges via a Trojan horse file.
https://bugzilla.mozilla.org/show_bug.cgi?id=1127481
http://www.securityfocus.com/bid/74611
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
http://www.mozilla.org/security/announce/2015/mfsa2015-58.html