The Updater in Mozilla Firefox before 48.0 on Windows allows local users to write to arbitrary files via vectors involving the callback application-path parameter and a hard link.
https://security.gentoo.org/glsa/201701-15
https://bugzilla.mozilla.org/show_bug.cgi?id=1246944
http://www.securitytracker.com/id/1036508
http://www.securityfocus.com/bid/92260
http://www.mozilla.org/security/announce/2016/mfsa2016-69.html