According to a Microsoft Security Advisory, attackers are taking advantage of a flaw that arises when an unspecified error occurs when processing a Word document. “This latest Word security flaw as “extremely critical” because it is unpatched and because malicious attackers are currently exploiting the vulnerability.”

This is not the same remote code execution flaw that was reported earlier. That bug was related to situations when a Word file was downloaded from a website or when a user opened certain email messages with attached MS Word files.