# CVE-2020-29583: Zyxel Multiple Products Use of Hard-Coded Credentials

> An attacker can use hardcoded credentials to gain admin access to Zyxel USG devices via SSH or web interface.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 3 Nov 2021 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Dec 2020
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-59jx-m3c4-2m9w

## What is CVE-2020-29583?

CVE-2020-29583 is a critical vulnerability in n/a, published on 22 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2020-29583?

It affects 30 products.


Products: Zyxel Atp100 Firmware, Zyxel Atp100w Firmware, Zyxel Atp200 Firmware, Zyxel Atp500 Firmware, Zyxel Atp700 Firmware, Zyxel Atp800 Firmware, Zyxel Usg1100 Firmware, Zyxel Usg110 Firmware, Zyxel Usg1900 Firmware, Zyxel Usg20-Vpn Firmware, Zyxel Usg20w-Vpn Firmware, Zyxel Usg210 Firmware, Zyxel Usg2200 Firmware, Zyxel Usg310 Firmware, Zyxel Usg40 Firmware, Zyxel Usg40w Firmware, Zyxel Usg60 Firmware, Zyxel Usg60w Firmware, Zyxel Usg Flex 100 Firmware, Zyxel Usg Flex 100w Firmware and 10 more.

## How do I fix CVE-2020-29583?

No fix has been published for CVE-2020-29583 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 3 May 2022.

## Is CVE-2020-29583 being exploited?

Yes. Attackers have exploited CVE-2020-29583 in the wild since at least 3 Nov 2021.

Public exploit code:

- Scanner for Zyxel products which are potentially vulnerable due to an undocumented user account (CVE-2020-29583) (github_poc): https://github.com/ruppde/scan_CVE-2020-29583
- ZyXel USG - Hardcoded Credentials (nuclei): http/cves/2020/CVE-2020-29583.yaml

## Other vulnerabilities in n/a

- [CVE-2023-33009](https://insights.sbomify.com/CVE-2023-33009/): Zyxel Multiple Firewalls Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2023-33010](https://insights.sbomify.com/CVE-2023-33010/): Zyxel Multiple Firewalls Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2023-28771](https://insights.sbomify.com/CVE-2023-28771/): Zyxel Multiple Firewalls OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2022-30525](https://insights.sbomify.com/CVE-2022-30525/): Zyxel Multiple Firewalls OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2020-9054](https://insights.sbomify.com/CVE-2020-9054/): Zyxel Multiple NAS Devices OS Command Injection (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-29583 and fix it if it is affected.

What it is: CVE-2020-29583 is a critical vulnerability in n/a, published on 22 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2020-29583 in the wild since at least 3 Nov 2021.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-29583/ (Markdown: https://insights.sbomify.com/CVE-2020-29583/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-29583
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-29583
- OSV: https://osv.dev/vulnerability/CVE-2020-29583

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-29583/
Summaries are generated and may contain mistakes; the official description above is the record.