Microsoft is warning us of yet another critical security flaw, but surprisingly this one is with fairly aging software. Windows 2000 and Windows ME are the only systems affected, and the software involved? IE 5.01 and IE 5.5. It's an offshoot of the WMF flaw that we saw a few weeks ago, though largely for the most part that has been fixed. The problem would result in a machine being compromised to the point of total control. Microsoft's suggestion is for those systems to upgrade to Internet Explorer 6, and I wholeheartedly agree with them. While the number of IE 5.5 and 5.01 users is dwindling, there are apparently enough to still make a security advisory worthwhile. If you happen to be one of the few affected upgrade soon.