WWBN AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 (master, 2026-08-23) contains a cross-site request forgery vulnerability in the CustomizeUser plugin's plugin/CustomizeUser/setSubscribers.json.php endpoint. The script reads users_id and ExtraSubscribers from $_REQUEST and calls User::setExtraSubscribers() without requiring a POST request or a valid CSRF token; autoCSRFGuard() is applied only to POST requests to *.json.php, and the mutation does not pass through ObjectYPT::save()/isUntrustedRequest(), so a cross-origin GET succeeds. An unauthenticated remote attacker who induces a logged-in administrator to load a crafted page (for example an <img> tag pointing at the endpoint) can forge the ExtraSubscribers count displayed on any user's channel. The CustomizeUser plugin is enabled by default, and no patched version was available at the time of reporting.