Word (or Word Viewer) in Microsoft Office 2000 SP3, XP SP3, 2003 SP2, 2004 for Mac, and Works Suite 2004, 2005, and 2006 does not properly parse certain rich text "property strings of certain control words," which allows user-assisted remote attackers to trigger heap corruption and execute arbitrary code, aka the "Word RTF Parsing Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1900
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2007/ms07-024
http://www.vupen.com/english/advisories/2007/1709
http://www.us-cert.gov/cas/techalerts/TA07-128A.html
http://www.securitytracker.com/id?1018013
http://www.securityfocus.com/bid/23836
http://www.securityfocus.com/archive/1/468871/100/200/threaded
http://www.kb.cert.org/vuls/id/555489
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=525