According to the MS10-087 security bulletin associated with the Office updates, Office 2007 and Office 2010 users are most at risk because attackers can hijack their machines simply by getting them to view a specially-crafted message in the Outlook preview pane.

In a second e-mail Wednesday, Bryant said that Office for Mac users were not vulnerable to the same types of attacks, although hackers could try to dupe them into opening malicious RTF (rich text format) documents attached to e-mail messages.

Microsoft has delayed security updates for the Mac version of Office before.