static int auth_login_timeout_cb(CALLBACK_FRAME) {
  pr_response_send_async(R_421,
    _("Login timeout (%d %s): closing control connection"), TimeoutLogin,
    TimeoutLogin != 1 ? "seconds" : "second");

  /* It's possible that any listeners of this event might terminate the
   * session process themselves (e.g. mod_ban).  So write out that the
   * TimeoutLogin has been exceeded to the log here, in addition to the
   * scheduled session exit message.
   */
  pr_log_pri(PR_LOG_INFO, "%s", "Login timeout exceeded, disconnected");
  pr_event_generate("core.timeout-login", NULL);

  pr_session_disconnect(&auth_module, PR_SESS_DISCONNECT_TIMEOUT,
    "TimeoutLogin");

  /* Do not restart the timer (should never be reached). */
  return 0;
}

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.