DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. In limited configurations, registered users may be able to craft a request to enumerate/access some portal files they should not have access to. This vulnerability is fixed in 9.13.8.
https://github.com/dnnsoftware/Dnn.Platform/security/advisories/GHSA-vxcm-4rwh-chpc