故障描述：
退出登录时出现”您当前的访问请求当中含有非法字符，已经被系统拒绝“错误。如下图：


解决方法：
打开 \source\class\discuz\discuz_application.php 文件
找到
private function _xss_check() {

    static $check = array('"', '>', '<', '\'', '(', ')', 'CONTENT-TRANSFER-ENCODING');

    if(isset($_GET['formhash']) && $_GET['formhash'] !== formhash()) {
        system_error('request_tainting');
    }

    if($_SERVER['REQUEST_METHOD'] == 'GET' ) {
        $temp = $_SERVER['REQUEST_URI'];
    } elseif(empty ($_GET['formhash'])) {
        $temp = $_SERVER['REQUEST_URI'].file_get_contents('php://input');
    } else {
        $temp = '';
    }

    if(!empty($temp)) {
        $temp = strtoupper(urldecode(urldecode($temp)));
        foreach ($check as $str) {
            if(strpos($temp, $str) !== false) {
                system_error('request_tainting');
            }
        }
    }

    return true;
}
修改为
private function _xss_check() {
    $temp = strtoupper(urldecode(urldecode($_SERVER['REQUEST_URI'])));
    if(strpos($temp, '<') !== false || strpos($temp, '"') !== false || strpos($temp, 'CONTENT-TRANSFER-ENCODING') !== false) {
        system_error('request_tainting');
    }
    return true;
}