High · published October 21, 2025
⚡ A semi-authenticated attacker can peek into your Zyxel devices! Just completing the first stage of 2FA is enough to access sensitive system configurations. 🔥 It's like getting a hotel key that opens all the doors to the maintenance rooms — once inside, you can easily find the blueprints for the entire building! This vulnerability could lead to a nightmare scenario where an attacker downloads your system configuration, exposing everything from network settings to firewall rules. With this information, they could potentially take control of your devices, putting your entire network at risk!
It's like getting a hotel key that opens all the doors to the maintenance rooms — once inside, you can easily find the blueprints for the entire building! The missing authorization flaw in Zyxel ATP and USG FLEX firmware allows semi-authenticated users — those who’ve only partially authenticated via 2FA — to access and download crucial system configurations without proper permissions.
This vulnerability could lead to a nightmare scenario where an attacker downloads your system configuration, exposing everything from network settings to firewall rules. With this information, they could potentially take control of your devices, putting your entire network at risk! Update your Zyxel devices to firmware version V5.40 or later immediately to patch this vulnerability. Additionally, review your 2FA implementation to ensure that all stages are properly secured and monitored. Regularly audit your system configurations to identify and mitigate any unauthorized access. You've got this! Follow these steps, and you'll be a security hero in no time! 🛡️
| Product | Versions | Fixed in |
|---|---|---|
| zyxel/zld | ≥ 4.32, < 5.41 | 5.41 |
| zyxel/zld | ≥ 4.50, < 5.41 | 5.41 |
| zyxel/zld | ≥ 4.16, < 5.41 | 5.41 |