Microsoft Excel 2002 SP3 and Office 2004 for Mac do not properly validate record information, which allows remote attackers to execute arbitrary code via a crafted Excel document, aka "Merge Cell Record Pointer Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6727
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-080