Mozilla responded to reports of vulnerabilities by pushing out a new version of Firefox on Friday.
In addition to the "pwn2own" vulnerability used to hack into systems running Firefox at the recent CanSecWest conference, version 3.08 of Firefox also addresses a separate critical flaw involving XSL Transforms.
Mozilla originally promised a browser update by Wednesday (1 April) but, in a pleasing departure for standard software development cycles, ended up pushing out the revamp several days ahead of schedule.
Firefox 3.0.8 release notes can be found here and there's more background on the brace of critical flaws address by the update in an advisory from Secunia here. ®