FKIE_CVE-2026-11405

Vulnerability from fkie_nvd - Published: 2026-07-06 20:16 - Updated: 2026-10-25 20:10
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
The web server binary /bin/httpd contains a hidden backdoor authentication mechanism in the login() function at 004c88b8. - The function contains a normal authentication path using MD5/hash-based password verification (prod_encode64/PasswordToMd5/check_rand_key). - After normal authentication fails, it calls GetValue("sys.rzadmin.password") to read a backdoor password from the device configuration. - It performs a direct strcmp() comparison (plaintext, not hashed) between the config value and the user-supplied password. A successful match grants role=2 (admin-level access) and creates a valid session. The rzadmin username is never checked — any username works with the backdoor
References
cret@cert.orghttps://cwe.mitre.org/data/definitions/912.html
cret@cert.orghttps://kb.cert.org/vuls/id/213560
af854a3a-2127-422b-91ae-364da2661108https://www.kb.cert.org/vuls/id/213560
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "firmware",
          "vendor": "Tenda",
          "versions": [
            {
              "status": "affected",
              "version": "US_AC6V2.0RTL_V15.03.06.51_multi_T"
            }
          ]
        },
        {
          "product": "firmware",
          "vendor": "Tenda",
          "versions": [
            {
              "status": "affected",
              "version": "US_AC5V1.0RTL_V15.03.06.48_multi_TDE01"
            }
          ]
        },
        {
          "product": "firmware",
          "vendor": "Tenda",
          "versions": [
            {
              "status": "affected",
              "version": "US_AC10V1.0re_V15.03.06.46_multi_TDE01"
            }
          ]
        },
        {
          "product": "firmware",
          "vendor": "Tenda",
          "versions": [
            {
              "status": "affected",
              "version": "US_W15EV1.0br_V15.11.0.5(1068_1567_841)_EN_TDE"
            }
          ]
        },
        {
          "product": "firmware",
          "vendor": "Tenda",
          "versions": [
            {
              "status": "affected",
              "version": "US_FH1201V1.0BR_V1.2.0.14(408)_EN_TD"
            }
          ]
        }
      ],
      "source": "cret@cert.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The web server binary /bin/httpd contains a hidden backdoor authentication mechanism in the login() function at 004c88b8.\r\n\r\n- The function contains a normal authentication path using MD5/hash-based password verification (prod_encode64/PasswordToMd5/check_rand_key).\r\n- After normal authentication fails, it calls GetValue(\"sys.rzadmin.password\") to read a backdoor password from the device configuration.\r\n- It performs a direct strcmp() comparison (plaintext, not hashed) between the config value and the user-supplied password.\r\n\r\nA successful match grants role=2 (admin-level access) and creates a valid session. The rzadmin username is never checked \u2014 any username works with the backdoor"
    },
    {
      "lang": "es",
      "value": "El binario del servidor web /bin/httpd contiene un mecanismo de autenticaci\u00f3n de puerta trasera oculto en la funci\u00f3n login() en 004c88b8.\n\n- La funci\u00f3n contiene una ruta de autenticaci\u00f3n normal utilizando verificaci\u00f3n de contrase\u00f1a basada en MD5/hash (prod_encode64/PasswordToMd5/check_rand_key).\n- Despu\u00e9s de que la autenticaci\u00f3n normal falla, llama a GetValue(\u2019sys.rzadmin.password\u2019) para leer una contrase\u00f1a de puerta trasera de la configuraci\u00f3n del dispositivo.\n- Realiza una comparaci\u00f3n strcmp() directa (texto plano, no hasheado) entre el valor de configuraci\u00f3n y la contrase\u00f1a proporcionada por el usuario.\n\nUna coincidencia exitosa otorga rol=2 (acceso a nivel de administrador) y crea una sesi\u00f3n v\u00e1lida. El nombre de usuario rzadmin nunca se verifica - cualquier nombre de usuario funciona con la puerta trasera"
    }
  ],
  "id": "CVE-2026-11405",
  "lastModified": "2026-10-25T20:10:00.147",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-11405",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-08T03:56:43.961536Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-06T20:16:29.450",
  "references": [
    {
      "source": "cret@cert.org",
      "url": "https://cwe.mitre.org/data/definitions/912.html"
    },
    {
      "source": "cret@cert.org",
      "url": "https://kb.cert.org/vuls/id/213560"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://www.kb.cert.org/vuls/id/213560"
    }
  ],
  "sourceIdentifier": "cret@cert.org",
  "vulnStatus": "Deferred"
}



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