An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.
https://github.com/dariosharp/CVE
https://github.com/tin-z/Stuff_and_POCs
https://www.zyxel.com/support/Zyxel_security_advisory_for_attacks_against_security_appliances.shtml