CVE-2020-28899: Zyxel LTE4506-m606 Firmware

Critical severity, CVSS 9.1. EPSS: 1.7% chance of exploitation in the next 30 days.

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.

Affected products

• Zyxel LTE4506-m606 Firmware: before v1.00\(abdo.6\)c0 (fixed in v1.00\(abdo.6\)c0)
• Zyxel LTE7460-m608 Firmware: before v1.00\(abfr.5\)c0 (fixed in v1.00\(abfr.5\)c0)
• Zyxel WAH7706 Firmware: before v1.00\(abbc.11\)c0 (fixed in v1.00\(abbc.11\)c0)

Published 2021-03-16. Last modified 2026-06-17.