Firefox 1.0.3 and 1.0.4, and Netscape 8.0.2, allows remote attackers to execute arbitrary code by tricking the user into using the "Set As Wallpaper" (in Firefox) or "Set as Background" (in Netscape) context menu on an image URL that is really a javascript: URL with an eval statement, aka "Firewalling."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11097
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A100011
http://www.vupen.com/english/advisories/2005/1075
http://www.securityfocus.com/bid/14242
http://www.securiteam.com/securitynews/5ZP0E0UGAK.html
http://www.redhat.com/support/errata/RHSA-2005-586.html
http://www.novell.com/linux/security/advisories/2005_45_mozilla.html
http://www.novell.com/linux/security/advisories/2005_18_sr.html
http://www.networksecurity.fi/advisories/netscape-multiple-issues.html
http://www.mozilla.org/security/announce/mfsa2005-47.html
http://www.mikx.de/firewalling/
http://www.ciac.org/ciac/bulletins/p-252.shtml