CVE-2017-11519
passwd_recovery.lua on the TP-Link Archer C9(UN)_V2_160517 allows an attacker to reset the admin password by leveraging a predictable random number generator seed. This is fixed in C9(UN)_V2_170511.
Date published : 2017-07-21
http://www.tp-link.com/en/download/Archer-C9_V2.html#Firmware
https://devcraft.io/posts/2017/07/21/tp-link-archer-c9-admin-password-reset.html