A vulnerability in NetCat CMS allows an attacker to send a specially crafted http request that can be used to check whether a user exists in the system, which could be a basis for further attacks.
This issue affects NetCat CMS v. 6.4.0.24126.2 and possibly others.Apply patch from vendor  https://netcat.ru/ https://netcat.ru/] . Versions 6.4.0.24248 and on have the patch.