An anonymous reader writes: Microsoft is warning users about a new Windows zero-day vulnerability that is being actively exploited in the wild and is primarily a risk to users on servers and workstations that open documents with embedded OLE objects. The vulnerability is currently being exploited via PowerPoint files. These specially crafted files contain a malicious OLE (Object Linking and Embedding) object. This is not the first time a vulnerability in OLE has been exploited by cybercriminals, however most previous OLE vulnerabilities have been limited to specific older versions of the Windows operating system. What makes this vulnerability dangerous is that it affects the latest fully patched versions of Windows.