CVEvulnerability

CVE-2020-29583

9.8 CRITICAL Known exploited Published 2020-12-22 Modified 2026-06-17 Official page ↗

CISA Known Exploited Vulnerability

Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability — Zyxel Multiple Products

Zyxel firewalls (ATP, USG, VM) and AP Controllers (NXC2500 and NXC5500) contain a use of hard-coded credentials vulnerability in an undocumented account ("zyfwp") with an unchangeable password.

Added to KEV: 2021-11-03
Remediation due: 2022-05-03
Ransomware use: Unknown
Required action: Apply updates per vendor instructions.
Notes: https://nvd.nist.gov/vuln/detail/CVE-2020-29583

Status: Analyzed
Published: 2020-12-22
Last modified: 2026-06-17
Assigner: [email protected]
CVSS 3.1 ([email protected]): 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0): 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0 ([email protected]): 10.0 HIGH — AV:N/AC:L/Au:N/C:C/I:C/A:C
Weaknesses: CWE-522

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.

Affected configurations

• zyxel usg20-vpn firmware 4.60 • zyxel usg20w-vpn firmware 4.60 • zyxel usg40 firmware 4.60 • zyxel usg40w firmware 4.60 • zyxel usg60 firmware 4.60 • zyxel usg60w firmware 4.60 • zyxel usg110 firmware 4.60 • zyxel usg210 firmware 4.60 • zyxel usg310 firmware 4.60 • zyxel usg1100 firmware 4.60 • zyxel usg1900 firmware 4.60 • zyxel usg2200 firmware 4.60 • zyxel zywall110 firmware 4.60 • zyxel zywall310 firmware 4.60 • zyxel zywall1100 firmware 4.60 • zyxel atp100 firmware 4.60 • zyxel atp100w firmware 4.60 • zyxel atp200 firmware 4.60 • zyxel atp500 firmware 4.60 • zyxel atp700 firmware 4.60 • zyxel atp800 firmware 4.60 • zyxel vpn50 firmware 4.60 • zyxel vpn100 firmware 4.60 • zyxel vpn300 firmware 4.60 • zyxel vpn1000 firmware 4.60 • zyxel usg flex 100 firmware 4.60 • zyxel usg flex 100w firmware 4.60 • zyxel usg flex 200 firmware 4.60 • zyxel usg flex 500 firmware 4.60 • zyxel usg flex 700 firmware 4.60

Weakness · CWE (1)

CWE-522 Insufficiently Protected Credentials weakness

References

http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf Broken Link
https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release Release Notes
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15 Release Notes
https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html 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/ Exploit, Third Party Advisory
https://www.zyxel.com/support/CVE-2020-29583.shtml Vendor Advisory
https://www.zyxel.com/support/security_advisories.shtml Vendor Advisory
http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf Broken Link
https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release Release Notes
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15 Release Notes
https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html 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/ Exploit, Third Party Advisory
https://www.zyxel.com/support/CVE-2020-29583.shtml Vendor Advisory
https://www.zyxel.com/support/security_advisories.shtml Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583 US Government Resource