The Mozilla Project has released Firefox 3.0.5 and 2.0.0.19 and SeaMonkey 1.1.14 to fix various security bugs. All users should upgrade.
There are a couple of other improvements of note in Firefox 3.0.5. Most interestingly, it no longer requires you to agree to a license on installation. Open source software doesn't need that and shouldn't do it. AppleScript was supposed to be at least marginally fixed in this release, but that doesn't seem to have happened so I'm still on 2.0.0.19 until at least the next release. :-(