    public function startTLS()
    {
        if (!$this->sendCommand('STARTTLS', 'STARTTLS', 220)) {
            return false;
        }
        // Begin encrypted connection
        if (!stream_socket_enable_crypto(
            $this->smtp_conn,
            true,
            STREAM_CRYPTO_METHOD_TLS_CLIENT
        )) {
            return false;
        }
        return true;
    }
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.