Less than a month since their debuts, first maintenance updates to Firefox 3 has come up with three critical vulnerabilities. One of them only affects Mac OS X while the remaining applied to all OS.
MFSA 2008-36 Crash with malformed GIF file on Mac OS X
MFSA 2008-35 Command-line URLs launch multiple tabs when Firefox not running
MFSA 2008-34 Remote code execution by overflowing CSS reference counter