Stored Cross-site Scripting (CWE-79) in the user management component in maalfer Pentestify before 1.1.1 allows an authenticated attacker to execute arbitrary JavaScript in the browser of another authenticated user via a crafted username, because the frontend escapes the username with escapeHTML() before interpolating it into the onclick attribute of the account deletion button, but the browser HTML-decodes attribute values before the JavaScript engine parses the handler, allowing an encoded single quote (') to break out of the string literal and inject arbitrary JavaScript that executes when the victim clicks the delete button for that account.
Upgrade to version 1.1.1 or higher.