The Web CGI Script on ZyXEL LTE4506-M606 V1.00(ABDO.2)C0 devices does not require authentication, which allows remote unauthenticated attackers (via crafted JSON action data to /cgi-bin/gui.cgi) to use all features provided by the router. Examples: change the router password, retrieve the Wi-Fi passphrase, send an SMS message, or modify the IP forwarding to access the internal network.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-28899
• https://www.zyxel.com/support/Zyxel-security-advisory-for-CGI-vulnerability-of-LTE.shtml