WWBN AVideo Live: OS command injection in on_publish.php execAsync via unescaped m3u8 URL

WWBN AVideo is an open source video platform. In 29.0 and earlier, there is a classic shell-metacharacter injection. The YPTSocket notification branch in plugin/Live/on_publish.php builds an execAsync() command line by string concatenation, single-quoting each argument but never calling escapeshellarg(). A ' in any of the three interpolated values ($users_id, $m3u8, $obj->liveTransmitionHistory_id) closes the quoted token and lets the attacker append arbitrary commands.