  unforwardIn(bindAddr, bindPort, cb) {
    if (!this._sock || !this._sock.writable)
      throw new Error('Not connected');

    // Send a request to stop forwarding us new connections for a particular
    // address and port

    const wantReply = (typeof cb === 'function');

    if (wantReply) {
      this._callbacks.push((had_err) => {
        if (had_err) {
          cb(had_err !== true
             ? had_err
             : new Error(`Unable to unbind from ${bindAddr}:${bindPort}`));
          return;
        }

        delete this._forwarding[`${bindAddr}:${bindPort}`];

        cb();
      });
    }

    this._protocol.cancelTcpipForward(bindAddr, bindPort, wantReply);

    return this;
  }
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.