CVE-2020-29583

9.8 CRITICAL CISA KEV - Actively Exploited
Published: December 22, 2020 Modified: November 07, 2025
View on NVD

Description

Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
Source: cve@mitre.org
Broken Link
https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
Source: cve@mitre.org
Release Notes
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
Source: cve@mitre.org
Release Notes
https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
Source: cve@mitre.org
Broken Link Third Party Advisory
https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/
Source: cve@mitre.org
Exploit Third Party Advisory
https://www.zyxel.com/support/CVE-2020-29583.shtml
Source: cve@mitre.org
Vendor Advisory
https://www.zyxel.com/support/security_advisories.shtml
Source: cve@mitre.org
Vendor Advisory
http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
Source: af854a3a-2127-422b-91ae-364da2661108
Broken Link
https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
Source: af854a3a-2127-422b-91ae-364da2661108
Release Notes
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
Source: af854a3a-2127-422b-91ae-364da2661108
Release Notes
https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
Source: af854a3a-2127-422b-91ae-364da2661108
Broken Link Third Party Advisory
https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Third Party Advisory
https://www.zyxel.com/support/CVE-2020-29583.shtml
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory
https://www.zyxel.com/support/security_advisories.shtml
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
US Government Resource

15 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
94.4%
100th percentile
Exploitation Status
Actively Exploited
Remediation due: 2022-05-03

Weaknesses (CWE)

CWE-522 CWE-522

Affected Vendors

zyxel

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