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CVE-2020-9054

9.8 · CRITICAL Actively Exploited
Published Mar 4, 2020 zyxel CWE-78 EPSS 99.99% (100th pctl)

Overview

CVE-2020-9054 is a critical-severity vulnerability affecting zyxel nas326_firmware. It was published on March 4, 2020 and has a CVSS 3.1 base score of 9.8 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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 arb

Remediation

Check the references section for vendor advisories and patches from zyxel. Update nas326_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status
zyxel nas326_firmware >= 0, < 5.21\(aazf.7\)c0 Affected
zyxel nas520_firmware >= 0, < 5.21\(aasz.3\)c0 Affected
zyxel nas540_firmware >= 0, < 5.21\(aatb.4\)c0 Affected
zyxel nas542_firmware >= 0, < 5.21\(abag.4\)c0 Affected
zyxel atp100_firmware >= 4.35, < 4.35\(abps.3\)c0 Affected
zyxel atp200_firmware >= 4.35, < 4.35\(abfw.3\)c0 Affected
zyxel atp500_firmware >= 4.35, < 4.35\(abfu.3\)c0 Affected
zyxel atp800_firmware >= 4.35, < 4.35\(abiq.3\)c0 Affected
zyxel usg20-vpn_firmware >= 4.35, < 4.35\(abaq.3\)c0 Affected
zyxel usg20w-vpn_firmware >= 4.35, < 4.35\(abar.3\)c0 Affected

Frequently Asked Questions

What is CVE-2020-9054?

CVE-2020-9054 is a critical-severity vulnerability affecting zyxel nas326_firmware. It was published on March 4, 2020 and has a CVSS 3.1 base score of 9.8 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2020-9054?

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2020-9054?

Check the references section for vendor advisories and patches from zyxel. Update nas326_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2020-9054?

CyberStrike's AI-powered security agents can automatically detect CVE-2020-9054 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.