	static public function getInstanceOf($_usernfo, $_tid)
	{
		if (! isset(self::$tickets[$_tid . '-' . $_usernfo['userid']])) {
			self::$tickets[$_tid . '-' . $_usernfo['userid']] = new ticket($_usernfo, $_tid);
		}
		return self::$tickets[$_tid . '-' . $_usernfo['userid']];
	}
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.