  function onError(err) {
    var which = (arguments.length >= 3 ? 'client' : 'server');
    assert(false, makeMsg(self.what, 'Unexpected ' + which + ' error: ' + err));
  }
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.