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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2020-9054 Detail

Description

Multiple ZyXEL network-attached storage (NAS) devices running firmware version 5.21 contain a pre-authentication command injection vulnerability, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable device. ZyXEL NAS devices achieve authentication by using the weblogin.cgi CGI executable. This program fails to properly sanitize the username parameter that is passed to it. If the username parameter contains certain characters, it can allow command injection with the privileges of the web server that runs on the ZyXEL device. Although the web server does not run as the root user, ZyXEL devices include a setuid utility that can be leveraged to run any command with root privileges. As such, it should be assumed that exploitation of this vulnerability can lead to remote code execution with root privileges. By sending a specially-crafted HTTP POST or GET request to a vulnerable ZyXEL device, a remote, unauthenticated attacker may be able to execute arbitrary code on the device. This may happen by directly connecting to a device if it is directly exposed to an attacker. However, there are ways to trigger such crafted requests even if an attacker does not have direct connectivity to a vulnerable devices. For example, simply visiting a website can result in the compromise of any ZyXEL device that is reachable from the client system. Affected products include: NAS326 before firmware V5.21(AAZF.7)C0 NAS520 before firmware V5.21(AASZ.3)C0 NAS540 before firmware V5.21(AATB.4)C0 NAS542 before firmware V5.21(ABAG.4)C0 ZyXEL has made firmware updates available for NAS326, NAS520, NAS540, and NAS542 devices. Affected models that are end-of-support: NSA210, NSA220, NSA220+, NSA221, NSA310, NSA310S, NSA320, NSA320S, NSA325 and NSA325v2


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cwe.mitre.org/data/definitions/78.html CERT/CC, CVE Third Party Advisory 
https://kb.cert.org/artifacts/cve-2020-9054.html CERT/CC, CVE Third Party Advisory  US Government Resource 
https://kb.cert.org/vuls/id/498544/ CERT/CC, CVE Third Party Advisory  US Government Resource 
https://krebsonsecurity.com/2020/02/zyxel-fixes-0day-in-network-storage-devices/ CERT/CC, CVE Exploit  Third Party Advisory 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-9054 CISA-ADP US Government Resource 
https://www.zyxel.com/support/remote-code-execution-vulnerability-of-NAS-products.shtml CERT/CC, CVE Vendor Advisory 

This CVE is in CISA's Known Exploited Vulnerabilities Catalog

Reference CISA's BOD 22-01 and Known Exploited Vulnerabilities Catalog for further guidance and requirements.

Vulnerability Name Date Added Due Date Required Action
Zyxel Multiple NAS Devices OS Command Injection Vulnerability 03/25/2022 04/15/2022 Apply updates per vendor instructions.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') cwe source acceptance level NIST   CERT/CC   CISA-ADP  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

11 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-9054
NVD Published Date:
03/04/2020
NVD Last Modified:
06/16/2026
Source:
CERT/CC