This is an excerpt from the e-mail that was sent to members of spreadfirefox.com this morning:
"The Spread Firefox Team became aware this week that the server hosting Spread Firefox, our community marketing site, has been accessed by unknown remote attackers who attempted to exploit a security vulnerability in TWiki software installed on the server. The TWiki software was disabled as soon as we were aware of the attempts to access SpreadFirefox.com. This exploit was limited to SpreadFirefox.com and did not affect mozilla.org web sites or Mozilla software."
The website is currently closed and is supposed to re-launch at the latest on October 15th. All users are encouraged to change their passwords but this will not be possible until the site is back online, this is the part of the announcement related to passwords:
"We will notify you again when the site is back up with instructions on how to change your password. (Note: We do use MD5 hashing on the passwords, but MD5 cannot protect all passwords against off-line dictionary style attacks.)"
This event does not undermine the security of Firefox although it does not make for good publicity.