Mozilla has updated Firefox to 3.0.9 version. You can use "Help -> Check for Updates" option to update your browser or it'll automatically notify you about the update very soon.
You can download its setup from following link:
Download Mozilla Firefox 3.0.9
This update fixes several security and stability issues. You can read about all changes at following link:
Firefox 3.0.9 Release Notes
You can also download using following link