Microsoft Excel Services on Microsoft SharePoint Server 2010 SP1 and SP2, Microsoft Excel Web Apps 2010 SP2, Microsoft Office Web Apps 2010 SP2, Microsoft Office Web Apps Server 2013 SP1 and Office Online Server allows remote attackers to perform cross-site scripting and run script with local user privileges via a crafted request, aka "Microsoft Office XSS Elevation of Privilege Vulnerability."
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-0195