Quick on the heels of Firefox 3.0.9 there is 3.0.10, which was released with a sole purpose: security. If you ever think Mozilla doesn't take security seriously, here's proof that they do.

The critical security issue has popped-up in 3.0.9 and concerns a crash in nsTextFrame::ClearTextRun(). Mostly users of the HTML Validator add-on were affected as it caused memory corruption similar to a previous security bug.

As always this is a recommended update for all Firefox users and can be obtained through Help -> Check for Updates if it has not yet appeared automatically.