For International Users:
This post is a guide to fix a serious security bug in Leancloud visitor counter, which is found by me and confirmed by Ivan.Nginx.
Someone could use this bug to change your visitor number easily and even add/delete records in your database.
This bug could only be fixed manually.
Warning: All NexT sites using Leancloud visitor counter that are not fixed and other sites integrated this function by similiar ways are considered unsecurity. Please fix it as soon as possible!
English version guide is under translating and will be released in few days.
2018.3.16: English version guide is here