Mozilla (makers of Firefox) have released a series of updates for both Firefox v2 and v3. The updates are all security related, and fix a dozen security flows. Half of the updates are flagged a critical.
Amongst the updates, one sticks out as really important, as it would allow an attacker the privilege to take over a machine after a session restore. Plus, another update could allow the execution of unwanted code through compromised Flash files.
Users should find that they have already be updated or be prompted to update shortly. The updates will take effect after the browser is restarted.
Users of Firefox 2 though are encouraged to download version 3 of Firefox, as v2 will no longer be supported / updated at the end of the year. Users can upgrade simply by popping into firefox.com and downloading version 3 from their.