WidzialniCMS is vulnerable to Reflected XSS in the /index.php endpoint. An attacker can prepare an URL that, when opened, results in arbitrary JavaScript execution in the victim's browser, allowing e.g session cookie theft.
This issue has been fixed in version 2.5.
Improper Neutralization of Input During Web Page Generation The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.