Mozilla has released a new version of its Firefox browser, 3.6.4, which besides the usual bug fixes and security patches contains a new feature that Mozilla describes as "Crash Protection". This is the much anticipated out-of-process plug-in (OOPP) "sandboxing" feature that prevents software such as Flash, SilverLight, and QuickTime from taking the whole browser down with them when they crash.

When a plug-in freezes or crashes, its contents are replaced with an error message informing the user of the issue while the browser itself will continue running. The new capability should significantly improve the browser's stability and is a first step towards full multi-process browsing, where not only plug-ins but tabs themselves are sandboxed into separate processes – something that has been touted in Google's Chrome from the start.

For now Firefox's crash protection will work on Windows and Linux only, though; it won't reach Mac OS X until Firefox 4 ships. Firefox 3.6.4 also fixed seven security vulnerabilities, four of them rated as critical and two moderate, so there's even more reason to upgrade. You can read the full release notes here.