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    CVE-2020-29583

    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.

    Published:Dec 22, 2020
    Last Modified:Nov 7, 2025
    EPS:Dec 22, 2020
    EPSS Score:0.94211
    CVSS Score:9.8

    CISA Notification

    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.

    Required Action:

    Apply updates per vendor instructions.

    Notes:

    No extra notes provided.

    Due Date
    May 3, 2022
    1592 days ago
    Alert Date
    Nov 3, 2021
    1773 days ago

    Affected Products

    Vendor
    Zyxel
    Product
    Atp100
    Vendor
    Zyxel
    Product
    Atp100 Firmware
    Vendor
    Zyxel
    Product
    Atp100w
    Vendor
    Zyxel
    Product
    Atp100w Firmware
    Vendor
    Zyxel
    Product
    Atp200
    Vendor
    Zyxel
    Product
    Atp200 Firmware
    Vendor
    Zyxel
    Product
    Atp500
    Vendor
    Zyxel
    Product
    Atp500 Firmware
    Vendor
    Zyxel
    Product
    Atp700
    Vendor
    Zyxel
    Product
    Atp700 Firmware
    Vendor
    Zyxel
    Product
    Atp800
    Vendor
    Zyxel
    Product
    Atp800 Firmware
    Vendor
    Zyxel
    Product
    Usg110
    Vendor
    Zyxel
    Product
    Usg1100
    Vendor
    Zyxel
    Product
    Usg1100 Firmware
    Vendor
    Zyxel
    Product
    Usg110 Firmware
    Vendor
    Zyxel
    Product
    Usg1900
    Vendor
    Zyxel
    Product
    Usg1900 Firmware
    Vendor
    Zyxel
    Product
    Usg20-vpn
    Vendor
    Zyxel
    Product
    Usg20-vpn Firmware
    Vendor
    Zyxel
    Product
    Usg20w-vpn
    Vendor
    Zyxel
    Product
    Usg20w-vpn Firmware
    Vendor
    Zyxel
    Product
    Usg210
    Vendor
    Zyxel
    Product
    Usg210 Firmware
    Vendor
    Zyxel
    Product
    Usg2200
    Vendor
    Zyxel
    Product
    Usg2200 Firmware
    Vendor
    Zyxel
    Product
    Usg310
    Vendor
    Zyxel
    Product
    Usg310 Firmware
    Vendor
    Zyxel
    Product
    Usg40
    Vendor
    Zyxel
    Product
    Usg40 Firmware
    Vendor
    Zyxel
    Product
    Usg40w
    Vendor
    Zyxel
    Product
    Usg40w Firmware
    Vendor
    Zyxel
    Product
    Usg60
    Vendor
    Zyxel
    Product
    Usg60 Firmware
    Vendor
    Zyxel
    Product
    Usg60w
    Vendor
    Zyxel
    Product
    Usg60w Firmware
    Vendor
    Zyxel
    Product
    Usg Flex 100
    Vendor
    Zyxel
    Product
    Usg Flex 100 Firmware
    Vendor
    Zyxel
    Product
    Usg Flex 100w
    Vendor
    Zyxel
    Product
    Usg Flex 100w Firmware
    Vendor
    Zyxel
    Product
    Usg Flex 200
    Vendor
    Zyxel
    Product
    Usg Flex 200 Firmware
    Vendor
    Zyxel
    Product
    Usg Flex 500
    Vendor
    Zyxel
    Product
    Usg Flex 500 Firmware
    Vendor
    Zyxel
    Product
    Usg Flex 700
    Vendor
    Zyxel
    Product
    Usg Flex 700 Firmware
    Vendor
    Zyxel
    Product
    Vpn100
    Vendor
    Zyxel
    Product
    Vpn1000
    Vendor
    Zyxel
    Product
    Vpn1000 Firmware
    Vendor
    Zyxel
    Product
    Vpn100 Firmware
    Vendor
    Zyxel
    Product
    Vpn300
    Vendor
    Zyxel
    Product
    Vpn300 Firmware
    Vendor
    Zyxel
    Product
    Vpn50
    Vendor
    Zyxel
    Product
    Vpn50 Firmware
    Vendor
    Zyxel
    Product
    Zywall110
    Vendor
    Zyxel
    Product
    Zywall1100
    Vendor
    Zyxel
    Product
    Zywall1100 Firmware
    Vendor
    Zyxel
    Product
    Zywall110 Firmware
    Vendor
    Zyxel
    Product
    Zywall310
    Vendor
    Zyxel
    Product
    Zywall310 Firmware

    Exploits

    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://github.com/ruppde/scan_CVE-2020-29583

    Related CVEs

    CVE-2025-9133 (CVSS 8.1) — A missing authorization vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.40, USG FLEX…
    CVE-2025-8078 (CVSS 7.2) — A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.32 through…
    CVE-2024-11667 (CVSS 7.5) — A directory traversal vulnerability in the web management interface of Zyxel ATP series firmware versions V5.0…
    CVE-2024-42061 (CVSS 6.1) — A reflected cross-site scripting (XSS) vulnerability in the CGI program "dynamic_script.cgi" of Zyxel ATP seri…
    CVE-2024-42060 (CVSS 7.2) — A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.32 through…
    CVE-2024-42059 (CVSS 7.2) — A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V5.00 through…
    CVE-2024-42058 (CVSS 7.5) — A null pointer dereference vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.38, USG F…
    CVE-2024-42057 (CVSS 8.1) — A command injection vulnerability in the IPSec VPN feature of Zyxel ATP series firmware versions from V4.32 th…
    CVE-2024-7203 (CVSS 7.2) — A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.60 through…
    CVE-2024-6343 (CVSS 4.9) — A buffer overflow vulnerability in the CGI program of Zyxel ATP series firmware versions from V4.32 through V5…

    References

    http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
    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://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.zyxel.com/support/CVE-2020-29583.shtml
    https://www.zyxel.com/support/security_advisories.shtml
    http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
    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://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.zyxel.com/support/CVE-2020-29583.shtml
    https://www.zyxel.com/support/security_advisories.shtml
    https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High