MaxSite CMS ushki Plugin cross site scripting

A vulnerability was found in MaxSite CMS up to 109.3. Impacted is an unknown function of the component ushki Plugin. Performing a manipulation of the argument f_ushka_new/f_ushk results in cross site scripting. Remote exploitation of the attack is possible. The exploit has been made public and could be used. Upgrading to version 109.4 is recommended to address this issue. The patch is named 8a3946bd0a54bfb72a4d57179fcd253f2c550cd7. Upgrading the affected component is recommended. The vendor was informed early about this issue. They classify it as a "Self-XSS". They deployed a countermeasure: "Nevertheless, we consider this a violation of secure coding standards. The lack of filtering via `htmlspecialchars()` has already been fixed in the latest patch to prevent incorrect data display."