CVE-2021-35033

Name: CVE-2021-35033
Creator: NVD / NIST
Published: 2021-11-23T22:15:07.623+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.40%

Last modified Jun 17, 2026

CVE-2021-35033 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. A vulnerability in specific versions of Zyxel NBG6818, NBG7815, WSQ20, WSQ50, WSQ60, and WSR30 firmware with pre-configured password management could allow an attacker to obtain root access of the device, if the local attacker dismantles the device and uses a USB-to-UART cable to connect the device, or if the remote assistance feature had been enabled by an authenticated user.. EPSS estimates a 0.40% chance of exploitation in the next 30 days.

Description

A vulnerability in specific versions of Zyxel NBG6818, NBG7815, WSQ20, WSQ50, WSQ60, and WSR30 firmware with pre-configured password management could allow an attacker to obtain root access of the device, if the local attacker dismantles the device and uses a USB-to-UART cable to connect the device, or if the remote assistance feature had been enabled by an authenticated user.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.40%

31.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zyxel	Nbg6818 Firmware	< 1.00\(absc.5\)c0
Zyxel	Nbg7815 Firmware	< 1.00\(absk.7\)c0
Zyxel	Wsq20 Firmware	< 1.00\(abof.11\)c0
Zyxel	Wsq50 Firmware	< 2.20\(abkj.7\)c0
Zyxel	Wsq60 Firmware	< 2.20\(abnd.8\)c0
Zyxel	Wsr30 Firmware	< 1.00\(abmy.12\)c0

References

https://www.tenable.com/security/research/tra-2022-06Exploit, Third Party Advisory
https://www.zyxel.com/support/Zyxel_security_advisory_for_pre-configured_password_management_vulnerability_of_home_routers_and_WiFi_systems.shtmlVendor Advisory
https://www.tenable.com/security/research/tra-2022-06Exploit, Third Party Advisory
https://www.zyxel.com/support/Zyxel_security_advisory_for_pre-configured_password_management_vulnerability_of_home_routers_and_WiFi_systems.shtmlVendor Advisory

Timeline

Published: Nov 23, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-35033?

How severe is CVE-2021-35033?

CVE-2021-35033 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2021-35033?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-35033?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST