The Mozilla Foundation has just released a number of security advisories concerning vulnerabilities in Mozilla Firefox, Thunderbird, and SeaMonkey. These vulnerabilities if exploited might allow a remote, unauthenticated attacker to execute arbitrary code or bypass security restrictions.
We recommend updating your current versions of any of the above products as soon as possible.
We would also recommend you set your software to automatically update. In Firefox for Mac, go to Preferences, Advanced, Updates tab and select the check box to automatically check for updates: Firefox, Add-Ons and Search Engines.
http://www.mozilla.org/security/known-vulnerabilities/