Microsoft Office Excel 2002 SP3, 2003 SP3, and 2007 SP1 and SP2; Office 2004 and 2008 for Mac; Open XML File Format Converter for Mac; Office Excel Viewer SP1 and SP2; and Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 do not properly parse the Excel file format, which allows remote attackers to execute arbitrary code via a crafted spreadsheet that causes memory to be interpreted as a different object type than intended, aka "Microsoft Office Excel Sheet Object Type Confusion Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-017