Mozilla has released Firefox 3.5.7.

Firefox 3.5.7 is an off-cycle stability update to Firefox 3.5.x that fixes

• Fixed a common stability issue
• Fixed a problem with how updates were being presented to users

Full details at: http://www.mozilla-europe.org/en/firefox/3.5.7/releasenotes/

If you are using the older 3.0.x version of Firefox then equivalent fixes are available via version 3.0.17.