CVE-2020-9054

KEV
Published: Mar 04, 2020 Last Modified: Nov 10, 2025
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,8
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: high
HIGH 10,0
Source: [email protected]
Access Vector: network
Access Complexity: low
Authentication: none
Confidentiality: complete
Integrity: complete
Availability: complete

Description

AI Translation Available

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

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,9431
Percentile
1,0th
Updated

EPSS Score Trend (Last 90 Days)

78

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Stable
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Availability Non-Repudiation
Potential Impacts:
Execute Unauthorized Code Or Commands Dos: Crash, Exit, Or Restart Read Files Or Directories Modify Files Or Directories Read Application Data Modify Application Data Hide Activities
Applicable Platforms
Technologies: AI/ML, Not Technology-Specific, Web Server
Likelihood of Exploit: High
View CWE Details
Operating System

Vpn300 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Vpn300 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abfc.3\)c0 (exclusive)
cpe:2.3:o:zyxel:vpn300_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Zywall110 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Zywall110 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aaaa.3\)c0 (exclusive)
cpe:2.3:o:zyxel:zywall110_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Nas520 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Nas520 Firmware
Version Range Affected
To 5.21\(aasz.3\)c0 (exclusive)
cpe:2.3:o:zyxel:nas520_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Atp200 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Atp200 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abfw.3\)c0 (exclusive)
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg60 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg60 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aaky.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg60_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Atp100 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Atp100 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abps.3\)c0 (exclusive)
cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Vpn100 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Vpn100 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abfv.3\)c0 (exclusive)
cpe:2.3:o:zyxel:vpn100_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Atp500 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Atp500 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abfu.3\)c0 (exclusive)
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Nas326 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Nas326 Firmware
Version Range Affected
To 5.21\(aazf.7\)c0 (exclusive)
cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg310 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg310 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aapj.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg310_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg60W Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg60W Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aakz.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg60w_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Vpn50 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Vpn50 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abhl.3\)c0 (exclusive)
cpe:2.3:o:zyxel:vpn50_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Nas540 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Nas540 Firmware
Version Range Affected
To 5.21\(aatb.4\)c0 (exclusive)
cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Zywall1100 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Zywall1100 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aaac.3\)c0 (exclusive)
cpe:2.3:o:zyxel:zywall1100_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Nas542 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Nas542 Firmware
Version Range Affected
To 5.21\(abag.4\)c0 (exclusive)
cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Zywall310 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Zywall310 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aaab.3\)c0 (exclusive)
cpe:2.3:o:zyxel:zywall310_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg110 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg110 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aaph.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg110_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Atp800 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Atp800 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abiq.3\)c0 (exclusive)
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg40 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg40 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aala.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg40_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg2200 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg2200 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abae.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg2200_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Vpn1000 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Vpn1000 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abip.3\)c0 (exclusive)
cpe:2.3:o:zyxel:vpn1000_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg210 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg210 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aapi.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg210_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg20-Vpn Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg20-Vpn Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abaq.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg20-vpn_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg20W-Vpn Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg20W-Vpn Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(abar.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg20w-vpn_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg40W Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg40W Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aalb.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg40w_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg1100 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg1100 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aapk.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg1100_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
Operating System

Usg1900 Firmware by Zyxel

Product Information
Vendor Zyxel
Product Usg1900 Firmware
Version Range Affected
From 4.35 (inclusive)
To 4.35\(aapl.3\)c0 (exclusive)
cpe:2.3:o:zyxel:usg1900_firmware:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
https://www.cisa.gov/known-exploited-vulnerabilities-catalo…
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020…
https://cwe.mitre.org/data/definitions/78.html
https://cwe.mitre.org/data/definitions/78.html
https://kb.cert.org/artifacts/cve-2020-9054.html
https://kb.cert.org/artifacts/cve-2020-9054.html
https://kb.cert.org/vuls/id/498544/
https://kb.cert.org/vuls/id/498544/
https://krebsonsecurity.com/2020/02/zyxel-fixes-0day-in-net…
https://krebsonsecurity.com/2020/02/zyxel-fixes-0day-in-network-storage-devices/
https://www.zyxel.com/support/remote-code-execution-vulnera…
https://www.zyxel.com/support/remote-code-execution-vulnerability-of-NAS-produc…
https://cwe.mitre.org/data/definitions/78.html
https://cwe.mitre.org/data/definitions/78.html
https://kb.cert.org/artifacts/cve-2020-9054.html
https://kb.cert.org/artifacts/cve-2020-9054.html
https://kb.cert.org/vuls/id/498544/
https://kb.cert.org/vuls/id/498544/
https://krebsonsecurity.com/2020/02/zyxel-fixes-0day-in-net…
https://krebsonsecurity.com/2020/02/zyxel-fixes-0day-in-network-storage-devices/
https://www.zyxel.com/support/remote-code-execution-vulnera…
https://www.zyxel.com/support/remote-code-execution-vulnerability-of-NAS-produc…