Kaseya Virtual System Administrator (VSA) 7.x before 7.0.0.33, 8.x before 8.0.0.23, 9.0 before 9.0.0.19, and 9.1 before 9.1.0.9 does not properly require authentication, which allows remote attackers to bypass authentication and (1) add an administrative account via crafted request to LocalAuth/setAccount.aspx or (2) write to and execute arbitrary files via a full pathname in the PathData parameter to ConfigTab/uploader.aspx.
Use CWE-287, Kaseya vendor hub and Virtual System Administrator product page to widen CVE-2015-6922 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2018-20753, CVE-2015-6589 and CVE-2019-15506 for nearby disclosures in the same product family.