WWBN AVideo is an open source video platform. Versions prior to 29.0 contain an unauthenticated Reflected XSS vulnerability through AVideo YouTubeAPI Gallery Pagination. The $_GET['search'] query parameter is concatenated directly into the href attribute of two pagination links in plugin/YouTubeAPI/gallerySection.php (lines 67 and 74) with no htmlspecialchars, no urlencode, and no allow-list check. An injected <script> element is then extracted by the AVideo Layout plugin and concatenated into a single trailing inline script block at the bottom of the page, where the browser executes it. Any unauthenticated attacker can lure a victim into following a crafted URL to execute arbitrary JavaScript under the AVideo origin, which can read non-HttpOnly cookies and issue authenticated AJAX requests as the victim, and when the victim is an administrator, it can perform any cookie-authenticated admin action (create user, promote to admin, change configuration, install plugin), escalating a single click into full administrative takeover. This issue has been patched by this commit: https://github.com/WWBN/AVideo/commit/f50fc033b7adb36f1ffd6640e7826468bdafdec3.