  def render_step(the_step, options = {})
    if the_step.nil? || the_step.to_s == Wicked::FINISH_STEP
      redirect_to_finish_wizard options
    else
      render the_step, options
    end
  end
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.