Microsoft Excel 2007 SP3, Excel 2010 SP2, Excel for Mac 2011, Excel 2016 for Mac, Office Compatibility Pack SP3, and Excel Viewer allow remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Memory Corruption Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-131