# CVE-2020-9054: Zyxel Multiple NAS Devices OS Command Injection Vulnerability

Source: https://junglewise.ai/threats/cve-2020-9054-zyxel-multiple-nas-devices-os-command-injection-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-03-25. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2020-9054 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2022-03-25

Multiple Zyxel NAS devices contain a pre-authentication command injection vulnerability in the weblogin.cgi executable due to improper sanitization of the username parameter. A remote, unauthenticated attacker can execute arbitrary code with root privileges by sending specially crafted HTTP requests. This vulnerability has been observed being exploited in the wild.

Vendors: [Zyxel](https://junglewise.ai/threats/vendors/zyxel).

## Quick answers

**Is CVE-2020-9054 exploited in the wild?** Yes. CVE-2020-9054 is known to be exploited in the wild, first recorded on 25 March 2022. Treat it as urgent.

**How severe is CVE-2020-9054?** Critical severity, with a CVSS score of 9.8, published 25 March 2022.

**Which products and versions are affected?** Zyxel NAS326 before V5.21(AAZF.7)C0; Zyxel NAS520 before V5.21(AASZ.3)C0; Zyxel NAS540 before V5.21(AATB.4)C0; Zyxel NAS542 before V5.21(ABAG.4)C0; and 10 more.

**Is there a fix for CVE-2020-9054?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2020-9054 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2020-9054?** Check whether you run Zyxel Multiple Network-Attached Storage (NAS) Devices. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Zyxel NAS326 before V5.21(AAZF.7)C0
- Zyxel NAS520 before V5.21(AASZ.3)C0
- Zyxel NAS540 before V5.21(AATB.4)C0
- Zyxel NAS542 before V5.21(ABAG.4)C0
- Zyxel NSA210 All (End-of-Support)
- Zyxel NSA220 All (End-of-Support)
- Zyxel NSA220+ All (End-of-Support)
- Zyxel NSA221 All (End-of-Support)
- Zyxel NSA310 All (End-of-Support)
- Zyxel NSA310S All (End-of-Support)
- Zyxel NSA320 All (End-of-Support)
- Zyxel NSA320S All (End-of-Support)
- Zyxel NSA325 All (End-of-Support)
- Zyxel NSA325v2 All (End-of-Support)

## Timeline

- 2020-02-24: disclosed: Public disclosure of 0-day vulnerability
- 2020-03-06: advisory: Initial NVD analysis published
- 2022-03-25: kev added: Added to CISA Known Exploited Vulnerabilities Catalog

## Related threats

- [Zyxel Multiple NAS Devices Command Injection Vulnerability](https://junglewise.ai/threats/cve-2023-27992-zyxel-multiple-nas-devices-command-injection-vulnerability)