The update provides 11 security fixes, including six with a top severity rating of 'critical'. If exploited, the flaws could allow an attacker to remotely execute code without user notification.
Other problems addressed in the patch include three flaws classified as 'moderate' and two as 'low'.
The Firefox 3.5.4 build also addresses a number of stability issues, and includes an update to the crash reporting tool which allows users to report crashes multiple times. An issue in which SSL pages would not properly load after a user cleared the browser's history archive has also been fixed.
Users can obtain the update directly through Mozilla's Firefox download site.