CVE-2020-29583

Exploitation

Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2021-11-03. Federal remediation due 2022-05-03.

SSVC decision

• ExploitationactiveCISA reports credible evidence of active exploitation.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

90.15% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 99.7% of scored records. A rank, not a probability.

NVD base score

9.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2020-12-22 00:00Z5 YR AGO

Last updated

2025-10-21 23:35Z1 YR AGO

Reserved

2020-12-06

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

• CWE-522Insufficiently Protected CredentialsClass

Data version

5.1

Document digest

0e2f90cf871a670cad531b5ee2f8d5a0b1befb4a150a8f4d0a01acb9b8094e0a

• www.zyxel.comhttps://www.zyxel.com/support/security_advisories.shtml
• ftp.zyxel.comhttp://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
• businessforum.zyxel.comhttps://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
• businessforum.zyxel.comhttps://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
• www.eyecontrol.nlhttps://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
• www.zyxel.comhttps://www.zyxel.com/support/CVE-2020-29583.shtml
• www.secpod.comhttps://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/
• www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583government-resource