Some vulnerabilities have been reported in Mozilla Firefox, which can be exploited by malicious people to conduct spoofing attacks, bypass certain security restrictions, and potentially compromise a user's system.

1) Errors in the JavaScript engine can be exploited to cause memory corruption and potentially to execute arbitrary code.

2) An error in the "addEventListener" method can be exploited to inject script into another site, circumventing the browser's same-origin policy. This could be used to access or modify sensitive information from the other site.

3) An error in the handling of XUL popups can be exploited to spoof parts of the browser such as the location bar.

Solution
Update to version 2.0.0.4 or 1.5.0.12.

Provided and/or discovered by
The vendor credits:
1) Boris Zbarsky, Eli Friedman, Georgi Guninski, Martijn Wargers, Olli Pettay, Brendan Eich, Igor Bukanov, Jesse Ruderman, moz_bug_r_a4, and Wladimir Palant
2) moz_bug_r_a4
3) Chris Thomas

Changelog
Further details available to Secunia VIM customers

Original Advisory
1) http://www.mozilla.org/security/announce/2007/mfsa2007-12.html
2) http://www.mozilla.org/security/announce/2007/mfsa2007-16.html
3) http://www.mozilla.org/security/announce/2007/mfsa2007-17.html

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers