一般是在未登录下使用首页搜索功能出现
解决方案如下：
\source\class\discuz的discuz_application.php
查找
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;
}
替换为：
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;
}
上传覆盖同名文件，后台更新缓存，重新登录退出看看是否解决了。(特别提醒：这个改变可能降低跨站攻击防护等级，所以非追求极致用户体验时慎用哦) | 
