# CVE-2020-29583: Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability

> CVE-2020-29583: Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability. CVSS 9.8 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2020-29583
Last updated: 2025-10-21T23:35:31Z

- Published: 2020-12-22 00:00 UTC · Updated: 2025-10-21 23:35 UTC · Assigner: mitre
- CVSS: 9.8 (CVSS 3.1) · Severity: Critical · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS: 90.2%, 100th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2021-11-03, federal due date 2022-05-03, ransomware use: Unknown

## 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.

## CISA required action

Apply updates per vendor instructions.

## Affected vendors and products

- Zyxel: Multiple Products

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2020-29583)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2020-29583)
- [http://ftp.zyxel.com/USG40/firmware/USG40\_4.60%28AALA.1%29C0\_2.pdf](http://ftp.zyxel.com/USG40/firmware/USG40_4.60(AALA.1%29C0_2.pdf)
- [https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release](https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release)
- [https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15](https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15)
- [https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html](https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html)
- [https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/](https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/)
- [https://www.zyxel.com/support/CVE-2020-29583.shtml](https://www.zyxel.com/support/CVE-2020-29583.shtml)
- [https://www.zyxel.com/support/security\_advisories.shtml](https://www.zyxel.com/support/security_advisories.shtml)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2020-29583 · Markdown: https://rewindex.com/cve/CVE-2020-29583.md · JSON: https://rewindex.com/api/v1/cves/CVE-2020-29583 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:50:05.766Z