Microsoft have just released a security patch to cover a 0 day exploit betweeen Outlook and Word. The vulnerability, outlined in Microsoft Security Advisory 2953095 is blocked by a Microsoft patch which disables opening RTF documents in Outlook: According to Microsoft "The vulnerability is a remote code execution vulnerability. The issue is caused when Microsoft Word parses specially crafted RTF-formatted data causing system memory to become corrupted in such a way that an attacker could execute arbitrary code."
The products affected include Word 2003, 2007, 2010, 2013,Microsoft Office for Mac 2011 and Word Automation Services on Microsoft SharePoint Server 2013.
The patch is available here https://support.microsoft.com/kb/2953095