Mozilla has pushed out an update to Firefox 3.5 to plug a critical security hole that Security Fix warned about this week. According to the SANS Internet Storm Center, there have been reports of public exploits for this flaw being used in the wild. The update brings Firefox 3.5 to version 3.5.1, and can be installed by selecting “Help,” and then “Check for Updates,” (3.5 users may also have the update auto-installed upon restarting the browser). This update appears to fix a number of other stability and security issues as well. If you took my advice to blunt the threat from the public exploit for this flaw, take a moment to undo the setting you changed earlier. That’s because my advice was disable the vulnerable component — Tracemonkey — which dramatically speeds up the rendering of Javascript in Web pages, and is among the most-touted improvements in Firefox 3.5. To