Just now, i have upgraded to Firefox 3.6.11 on my Ubuntu, but 3.6.12 has been released to fix one nasty vulnerability discovered by Morten Kråkvik described on this article: Heap buffer overflow mixing document.write and DOM insertion.
I think it will be included in tomorrow's update in all major Linux distros. Just wait and see
Mozilla has done a great job of giving their user a better and safer experience in browsing the Internet with their products. That's why i sticked to Firefox even though Google Chrome is getting more and more interesting on each release.