DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Starting in version 9.0.0 and prior to versions 9.13.10 and 10.2.0, a content editor could inject scripts in module headers/footers that would run for other users. Versions 9.13.10 and 10.2.0 contain a fix for the issue.
https://github.com/dnnsoftware/Dnn.Platform/security/advisories/GHSA-jjwg-4948-6wxp