An information disclosure vulnerability exists when Microsoft Office software reads out of bound memory due to an uninitialized variable, which could disclose the contents of memory, aka "Microsoft Office Information Disclosure Vulnerability." This affects Word, Microsoft SharePoint Server, Microsoft Office Word Viewer, Microsoft Excel Viewer, Microsoft SharePoint, Microsoft Office.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8378