Mozilla has released an updated version, 10.0.1, of the Firefox browser for Windows, Linux, and Mac OS X. This version corrects a critical security vulnerability in the recently-released Firefox 10, as well as a bug affecting Java applets. More details are available in the Release Notes.
You can get the new version via the built-in update mechanism (Help / About Firefox / Check for Updates), or you can download an installation package, in your language of choice. Because of the security fix, I recommend that you upgrade your system to the new release as soon as you conveniently can.
Mozilla is indicating that version 10.0.1 will continue to be an Extended Support release.