There is a new crucial vulnerablity out for Explorer 5 and up. The patch is not yet available from Windows Update, so here is the location where more information can be found. I'd highly reccomend anyone using Explorer to download and install the patch.

<a href="http://www.microsoft.com/windows/ie/downloads/critical/q316059/default.asp" target="_blank">http://www.microsoft.com/windows/ie/downloads/critical/q316059/default.asp</a>