CVE-2020-29583: Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 316 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 90.2%
EPSS score, percentile 99.8 of all scored records
- How severe?
- 9.8 Critical
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline . Apply updates per vendor instructions.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2020-29583 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 3 May 2022.
- The CVE record was published on 22 Dec 2020, 316 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 90.2% (percentile 99.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-522: Insufficiently Protected Credentials
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
- zyxel.com
- ftp.zyxel.com
- businessforum.zyxel.com
- businessforum.zyxel.com
- eyecontrol.nl
- zyxel.com
- secpod.com
More exploited Zyxel vulnerabilities
- CVE-2026-7273: Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
- CVE-2024-40890: Zyxel DSL CPE OS Command Injection Vulnerability
- CVE-2024-40891: Zyxel DSL CPE OS Command Injection Vulnerability
- CVE-2024-11667: Zyxel Multiple Firewalls Path Traversal Vulnerability
- CVE-2017-6884: Zyxel EMG2926 Routers Command Injection Vulnerability
- CVE-2017-18368: Zyxel P660HN-T1A Routers Command Injection Vulnerability