Microsoft SharePoint Enterprise Server 2016 allows an elevation of privilege vulnerability to due how specially crafted web requests are sanitized, aka "Microsoft SharePoint Elevation of Privilege Vulnerability". This CVE is unique from CVE-2018-0909, CVE-2018-0910. CVE-2018-0911, CVE-2018-0912, CVE-2018-0913 CVE-2018-0914, CVE-2018-0915, CVE-2018-0916, CVE-2018-0917, CVE-2018-0923, CVE-2018-0944 and CVE-2018-0947.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0921