AVideo: Missing Authorization in Playlist Schedule Creation Allows Cross-User Broadcast Hijacking

Summary

The plugin/PlayLists/View/Playlists_schedules/add.json.php endpoint allows any authenticated user with streaming permission to create or modify broadcast schedules targeting any playlist on the platform, regardless of ownership. When the schedule executes, the rebroadcast runs under the victim playlist owner's identity, allowing content hijacking and stream disruption.

Details

The endpoint at plugin/PlayLists/View/Playlists_schedules/add.json.php performs only a capability check, not an ownership check:

// add.json.php:14 — only checks if user CAN stream, not if they OWN the playlist
if (!User::canStream()) {
    forbiddenPage(__("You cannot livestream"));
}

// Line 18-19: attacker-controlled playlists_id is used directly
$o = new Playlists_schedules(@$_POST['id']);
$o->setPlaylists_id($_POST['playlists_id']);

The Playlists_schedules::save() method (line 182) only validates that playlists_id is non-empty — no ownership check:

public function save()
{
    if(empty($this->playlists_id)){
        _error_log("Playlists_schedules::save playlists_id is empty");
        return false;
    }
    // ...
    return parent::save();
}

When the schedule triggers via plugin/PlayLists/run.php, the rebroadcast executes under the playlist owner's user ID, not the schedule creator's:

// run.php:55 — uses playlist owner's ID
$pl = new PlayList($ps->playlists_id);
$response = Rebroadcaster::rebroadcastVideo(
    $ps->current_videos_id,
    $pl->getUsers_id(),  // <-- victim's user ID
    Playlists_schedules::getPlayListScheduledIndex($value['id']),
    $title
);

By contrast, all other playlist modification endpoints properly verify ownership via PlayLists::canManagePlaylist():

// PlayLists.php:55-68
static function canManagePlaylist($playlists_id)
{
    if (!User::isLogged()) return false;
    if (self::canManageAllPlaylists()) return true;
    $pl = new PlayList($playlists_id);
    if ($pl->getUsers_id() == User::getId()) return true;
    return false;
}

This check is used in saveShowOnTV.json.php:43, playListToSerie.php:24, and getPlaylistButtons.php:34, but is entirely absent from add.json.php.

Additionally, the delete.json.php endpoint requires User::isAdmin() (line 11), making the disparity with add.json.php even clearer.

When providing an existing schedule via POST (line 18), no ownership check is performed on the existing schedule record either, allowing modification of any schedule on the platform.