Emlog vulnerable to Stored Cross-site Scripting

Emlog is an open source website building system. Version 2.5.13 has a stored cross-site scripting vulnerability that allows any registered user to construct malicious JavaScript, inducing all website users to click. In `/admin/comment.php`, the parameter `perpage_num` is not validated and is directly stored in the `admin_commend_perpage_num` field of the `emlog_options` table in the database. Moreover, the output is not filtered, resulting in the direct output of malicious code. As of time of publication, it is unclear if a patch exists.