PHPOK V3.0 企业站程序本地文件包含漏洞

看代码：

app\www\control\js.php
function index_f()
        {
                $act = $this->trans_lib->safe("act");
                if(file_exists(ROOT_JS.$act.".php"))
                {
                        include(ROOT_JS.$act.".php");
                }
                else
                {
                        echo "ERROR";
                }
                exit();
        }