Firefox 1.0 does not prevent the user from dragging an executable file to the desktop when it has an image/gif content type but has a dangerous extension such as .bat or .exe, which allows remote attackers to bypass the intended restriction and execute arbitrary commands via malformed GIF files that can still be parsed by the Windows batch file parser, aka "firedragging."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A100033
https://bugzilla.mozilla.org/show_bug.cgi?id=279945
http://www.securityfocus.com/bid/12468
http://www.novell.com/linux/security/advisories/2006_04_25.html
http://www.mozilla.org/security/announce/mfsa2005-25.html
http://www.gentoo.org/security/en/glsa/glsa-200503-30.xml
http://www.gentoo.org/security/en/glsa/glsa-200503-10.xml