Integer underflow in Microsoft Excel 2002 SP3, 2003 SP3, 2007 SP2, and 2010; Office 2004 and 2008 for Mac; Open XML File Format Converter for Mac; Excel Viewer SP2; and Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 allows remote attackers to execute arbitrary code via a crafted 400h substream in an Excel file, which triggers a stack-based buffer overflow, aka "Excel Integer Overrun Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12612
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-021
http://www.vupen.com/english/advisories/2011/0940
http://www.us-cert.gov/cas/techalerts/TA11-102A.html
http://www.securitytracker.com/id?1025337
http://www.securityfocus.com/bid/47201
http://secunia.com/secunia_research/2011-31