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CVE-2020-29583

97
FAUCET Score

CVE-2020-29583 is a critical vulnerability affecting Zyxel USG devices, specifically firmware version 4.60, due to an undocumented "zyfwp" account with a hardcoded, unchangeable password accessible in cleartext within the firmware. This allows unauthenticated attackers to gain administrative access via SSH or the web interface. With a CVSS score of 9.8 (CRITICAL) and a FAUCET Risk Score of 100/100, the vulnerability poses a severe risk, enabling full compromise of affected devices. It is actively exploited in the wild, as confirmed by its presence in the KEV catalog and recent threat intelligence, with community discussion and media coverage highlighting its widespread impact.

Impacted Technologies

VendorProductVersion(s)CPE
4.60CPE matchmatch criteria
cpe:2.3:o:zyxel:usg20-vpn_firmware:4.60:*:*:*:*:*:*:*
4.60CPE matchmatch criteria
cpe:2.3:o:zyxel:usg20w-vpn_firmware:4.60:*:*:*:*:*:*:*
4.60CPE matchmatch criteria
cpe:2.3:o:zyxel:usg40_firmware:4.60:*:*:*:*:*:*:*
4.60CPE matchmatch criteria
cpe:2.3:o:zyxel:usg40w_firmware:4.60:*:*:*:*:*:*:*
4.60CPE matchmatch criteria
cpe:2.3:o:zyxel:usg60_firmware:4.60:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
90.05%
Probability of exploitation in next 30 days
EPSS Percentile
99.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · Nov 3, 2021
Nuclei: CVE-2020-29583 · May 25, 2023
This CVE's current EPSS score of 0.9005 is in the 99th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
ftp.zyxel.com / USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
Broken Link
businessforum.zyxel.com / discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
Release Notes
businessforum.zyxel.com / discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
Release Notes
eyecontrol.nl / blog/undocumented-user-account-in-zyxel-products.html
Broken LinkThird Party Advisory
secpod.com / blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583
ExploitThird Party Advisory
zyxel.com / support/CVE-2020-29583.shtml
Vendor Advisory
zyxel.com / support/security_advisories.shtml
Vendor Advisory