Microsoft Word 2007 SP3 and 2010 SP1 and SP2, and Office Compatibility Pack SP3, allocates memory incorrectly for file conversions from a binary (aka .doc) format to a newer format, which allows remote attackers to execute arbitrary code via a crafted document, aka "Microsoft Office File Format Converter Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-017