  x11(chan, initWindow, maxPacket, cfg) {
    if (!this._server)
      throw new Error('Server-only method called in client mode');

    const addrLen = Buffer.byteLength(cfg.originAddr);
    let p = this._packetRW.write.allocStart;
    const packet = this._packetRW.write.alloc(
      1 + 4 + 3 + 4 + 4 + 4 + 4 + addrLen + 4
    );

    packet[p] = MESSAGE.CHANNEL_OPEN;

    writeUInt32BE(packet, 3, ++p);
    packet.utf8Write('x11', p += 4, 3);

    writeUInt32BE(packet, chan, p += 3);

    writeUInt32BE(packet, initWindow, p += 4);

    writeUInt32BE(packet, maxPacket, p += 4);

    writeUInt32BE(packet, addrLen, p += 4);
    packet.utf8Write(cfg.originAddr, p += 4, addrLen);

    writeUInt32BE(packet, cfg.originPort, p += addrLen);

    this._debug && this._debug(
      `Outbound: Sending CHANNEL_OPEN (r:${chan}, x11)`
    );
    sendPacket(this, this._packetRW.write.finalize(packet));
  }
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.