Zyxel USG Hardcoded Default Password (CVE-2020-29583)

critical Nessus Plugin ID 172582


The remote security gateway is affected by a hardcoded default password vulnerability.


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.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Upgrade to Zyxel USG version 4.60 or later.

See Also


Plugin Details

Severity: Critical

ID: 172582

File Name: zyxel_usg_cve-2020-29583.nasl

Version: 1.2

Type: combined

Family: Firewalls

Published: 3/15/2023

Updated: 3/16/2023

Supported Sensors: Nessus

Risk Information


Risk Factor: High

Score: 8.9


Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2020-29583


Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.4

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C

Vulnerability Information

CPE: cpe:/h:zyxel:usg_flex

Required KB Items: installed_sw/Zyxel Unified Security Gateway (USG)

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/22/2020

Vulnerability Publication Date: 12/22/2020

CISA Known Exploited Vulnerability Due Dates: 5/3/2022

Reference Information

CVE: CVE-2020-29583