  cleanup(err) {
    const channels = this._channels;
    this._channels = {};
    this._cur = -1;
    this._count = 0;

    const chanIDs = Object.keys(channels);
    const client = this._client;
    for (let i = 0; i < chanIDs.length; ++i) {
      const id = +chanIDs[i];
      onCHANNEL_CLOSE(client, id, channels[id], err, true);
    }
  }
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.