phpMyFAQ is an open source FAQ web application. Starting no later than version 3.2.10 and prior to version 4.0.2, an attacker can inject malicious HTML content into the FAQ editor at `http[:]//localhost/admin/index[.]php?action=editentry`, resulting in a complete disruption of the FAQ page's user interface. By injecting malformed HTML elements styled to cover the entire screen, an attacker can render the page unusable. This injection manipulates the page structure by introducing overlapping buttons, images, and iframes, breaking the intended layout and functionality. Exploiting this issue can lead to Denial of Service for legitimate users, damage to the user experience, and potential abuse in phishing or defacement attacks. Version 4.0.2 contains a patch for the vulnerability.