DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Prior to version 10.1.0, DNN’s URL/path handling and template rendering can allow specially crafted input to be reflected into a user profile that is returned to the browser. In these cases, the application does not sufficiently neutralize or encode characters that are meaningful in HTML, so an attacker can cause a victim’s browser to interpret attacker-controlled content as part of the page’s HTML. This issue has been patched in version 10.1.0.