Mozilla Firefox, Thunderbird and SeaMonkey have been found to be vulnerable to an issue in which domain name certificates are dealt with between client browsers and CA servers. The issue is currently unpatched for all products except for users of Firefox 3.5. It is suggested to not browse untrusted sites or open emails from untrusted sources.
More information can be found at:
Posted by Brad Graves on August 05, 2009, in Handlers Log.