SiberianCMS HTTP GET Request flat cross site scripting

A vulnerability was found in SiberianCMS 4.20.6. It has been rated as problematic. Affected by this issue is some unknown functionality of the file /app/sae/design/desktop/flat of the component HTTP GET Request Handler. The manipulation leads to cross site scripting. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.