There’s another major bug in one of the IE ActiveX controls installed as part of Windows. It allows any web site to run arbitrary code on your system via malformed HTTP requests.
Microsoft have issued a fix for this one. The problem is, the original broken ActiveX control is still out there, and is signed as trusted code with a Microsoft signature which doesn’t expire. So nefarious web sites can simply request the old, broken version be downloaded and executed in preference to the new one, then use the old security hole to reformat your hard drive.
So the only real fix is to turn off ActiveX. Microsoft are advising that users remove Microsoft from the list of trusted software developers.
Or just don’t use IE for web browsing.
What a lovely piece of petard-hoisting.