Firefox 1.0.5 includes several fixes to boost stability and patches two critical and four high security risks. A total of twelve security leaks were addressed in this update. Here's a list of all security updates in 1.0.5:
MFSA 2005-56 Code execution through shared function objectsFirefox 1.0.5 can be downloaded here for Windows, Linux and Mac OS X.
MFSA 2005-55 XHTML node spoofing
MFSA 2005-53 Standalone applications can run arbitrary code through the browser
MFSA 2005-52 Same origin violation: frame calling top.focus()
MFSA 2005-51 The return of frame-injection spoofing
MFSA 2005-50 Possibly exploitable crash in InstallVersion.compareTo()
MFSA 2005-49 Script injection from Firefox sidebar panel using data:
MFSA 2005-48 Same-origin violation with InstallTrigger callback
MFSA 2005-47 Code execution via "Set as Wallpaper"
MFSA 2005-45 Content-generated event vulnerabilities