The DevExpress Resource Handler (ASPxHttpHandlerModule) in DevExpress ASP.NET Web Forms Build v19.2.3 does not verify the referenced objects in the /DXR.axd?r= HTTP GET parameter. This leads to an Insecure Direct Object References (IDOR) vulnerability which allows attackers to access the application source code. NOTE: the vendor disputes this because the retrieved source code is only the DevExpress client-side application code that is, of course, intentionally readable by web browsers (a site's custom code and data is never accessible via an IDOR approach).