Draytek Vigor Routers firmware versions below 3.9.6/4.2.4, Access Points firmware versions below v1.4.0, Switches firmware versions below 2.6.7, and Myvigor firmware versions below 2.3.2 were discovered to use hardcoded encryption keys which allows attackers to bind any affected device to their own account. Attackers are then able to create WCF and DrayDDNS licenses and synchronize them from the website.

An issue was discovered on certain DrayTek Vigor routers before July 2022 such as the Vigor3910 before 4.3.1.1. /cgi-bin/wlogin.cgi has a buffer overflow via the username or password to the aa or ab field.