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CVE-2020-29583

Published: Dec 22, 2020Updated: Nov 7, 2025 Sources: CVE List NVD BDUCWE-522
NVD MITRE
9.8CVSSCRITICAL
EPSS Score
90.0%
Top 0.2%
CISA KEV
Active Exploitation
Since Nov 3, 2021
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-522

Affected Products

usg20-vpn firmwarezyxelNetworking Infrastructure
usg20w-vpn firmwarezyxelNetworking Infrastructure
usg40 firmwarezyxelNetworking Infrastructure
usg40w firmwarezyxelNetworking Infrastructure
usg60 firmwarezyxelNetworking Infrastructure
zyxelcommercialTWNetworking Infrastructureaka zyxel communications corp.
and 56 more affected products View all →

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Nov 3, 2021
Remediation due:May 3, 2022

Required action: Apply updates per vendor instructions.

Official Patch Available
Am I actually vulnerable?1 Nuclei template available — see how to check your systems. How to verify Rather we check it for you?We'll check your whole external perimeter for exposure — free. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

MITRE ATT&CK

2 techniques
Credential Access
View detailed technique mapping

References

http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
ftp.zyxel.com
https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
businessforum.zyxel.com
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
businessforum.zyxel.com
and 10 more references View all →

Timeline

Published
Dec 22, 2020
Added to CISA KEV
Nov 3, 2021
Last Updated
Nov 7, 2025

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