Mozilla Corporation has released patches to fix critical security flaws

The Firefox update, which was in the process of being automatically delivered to Firefox 1.5 users Friday, addresses 12 security flaws. The release also includes some fixes designed to make the browser more stable, according to a statement on the Mozilla Web site.
Intrusion Risked

Five of the browser flaws are serious enough that an attacker could possibly use them to run unauthorized software on an unpatched system, Mozilla says. Security vendor Secunia rates this update as "highly critical," its second-highest rating of importance.

There are a couple of mitigating factors, however. First, hackers must still develop code that takes advantage of these flaws before users can be attacked. Second, a user would need to be tricked into visiting a malicious Web site for the attack to occur.

Eight bugs have been fixed in Thunderbird, one of which is considered critical by Mozilla.

Mozilla is offering more details on the Firefox vulnerabilities, as well as descriptions of the Thunderbird flaws.