i downloaded it and am using it too -
but I did find this article-
[Since Mozilla is still working on a fix, the researchers won't share details about the problem. Tipping Point ranked the severity of the vulnerability as high, but said that users would have to click on a link in an e-mail or visit a malicious Web page before being affected. The issue affects users of Firefox 3.0 as well as Firefox 2.0.]

http://infotech.indiatimes.com/articleshow/3148636.cms
http://www.linuxsecurity.com/content/view/138784?rdf
http://www.linuxworld.com/news/2008/...rss-linux-news

I'm sure they get a fix set up quickly- or maybe it isn't the problem as it's portrayed to be in the articles.