Firefox 2.0.0.5 is now available for download. The release notes have not been updated yet. So no word on what was fixed/updated.

http://www.mozilla.com/en-US/firefox/

The latest Release Notes document:
http://www.mozilla.com/en-US/firefox/2.0.0.5/releasenotes/

Known Vulnerabilities in Mozilla Products -> Fixed in Firefox 2.0.0.5:
http://www.mozilla.org/projects/security/known-vulnerabilities.html#Firefox

Secunia's Mozilla Firefox Multiple Vulnerabilities advisory:
http://secunia.com/advisories/26095/
Severity: Highly Critical (4/5)