  doFatalError: (protocol, msg, level, reason) => {
    let err;
    if (DISCONNECT_REASON === undefined)
      ({ DISCONNECT_REASON } = require('./utils.js'));
    if (msg instanceof Error) {
      // doFatalError(protocol, err[, reason])
      err = msg;
      if (typeof level !== 'number')
        reason = DISCONNECT_REASON.PROTOCOL_ERROR;
      else
        reason = level;
    } else {
      // doFatalError(protocol, msg[, level[, reason]])
      err = makeError(msg, level, true);
    }
    if (typeof reason !== 'number')
      reason = DISCONNECT_REASON.PROTOCOL_ERROR;
    protocol.disconnect(reason);
    protocol._destruct();
    protocol._onError(err);
    return Infinity;
  },
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.