WWBN AVideo is an open source video platform. In versions 29.0 and prior, the locale save endpoint ("locale/save.php") constructs a file path by directly concatenating "$_POST['flag']" into the path at line 30 without any sanitization. The "$_POST['code']" parameter is then written verbatim to that path via "fwrite()" at line 40. An admin attacker (or any user who can CSRF an admin, since no CSRF token is checked and cookies use "SameSite=None") can traverse out of the "locale/" directory and write arbitrary ".php" files to any writable location on the filesystem, achieving Remote Code Execution. Commit 57f89ffbc27d37c9d9dd727212334846e78ac21a fixes the issue.