  serviceAccept(svcName) {
    if (!this._server)
      throw new Error('Server-only method called in client mode');

    const svcNameLen = Buffer.byteLength(svcName);
    let p = this._packetRW.write.allocStart;
    const packet = this._packetRW.write.alloc(1 + 4 + svcNameLen);

    packet[p] = MESSAGE.SERVICE_ACCEPT;

    writeUInt32BE(packet, svcNameLen, ++p);
    packet.utf8Write(svcName, p += 4, svcNameLen);

    this._debug && this._debug(`Outbound: Sending SERVICE_ACCEPT (${svcName})`);
    sendPacket(this, this._packetRW.write.finalize(packet));

    if (this._server && this._banner && svcName === 'ssh-userauth') {
      const banner = this._banner;
      this._banner = undefined; // Prevent banner from being displayed again
      const bannerLen = Buffer.byteLength(banner);
      p = this._packetRW.write.allocStart;
      const packet = this._packetRW.write.alloc(1 + 4 + bannerLen + 4);

      packet[p] = MESSAGE.USERAUTH_BANNER;

      writeUInt32BE(packet, bannerLen, ++p);
      packet.utf8Write(banner, p += 4, bannerLen);

      writeUInt32BE(packet, 0, p += bannerLen); // Empty language tag

      this._debug && this._debug('Outbound: Sending USERAUTH_BANNER');
      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.