Microsoft warns of a dangerous vulnerability in Internet Explorer (under Windows XP and Windows Server 2003). This time, the hole was found in the Video ActiveX Control element (msvidctl.dll library), through which an attacker could gain remote access to the machine as a local user.
You can disable the Video ActiveX Control element on this page (just in case, Microsoft recommends that users also do this on Vista). In the near future there will be a patch covering the hole.
Information about this vulnerability was passed to Microsoft by independentexperts . There is every reason to believe that the vulnerability was previously known to hackers, and in the near future, even before the release of the patch, working exploits may appear (or have already appeared).