« Volver al listado

CVE-2026-84961

Estado: AnalizadaCrítica (9.1)—

undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value as JSON. Because JSON cannot represent functions, any function-valued TLS option, such as a caller-supplied checkServerIdentity callback or a custom connector inside the connect option, is silently discarded before it reaches the TLS layer. As a result a peer whose certificate the application's custom checkServerIdentity was written to reject, but which still passes Node's default hostname and chain checks, is accepted when reached through BalancedPool.

Leer descripción completaMostrar menos

The Client, Pool, and Agent dispatchers are not affected because they extract the connect and tls options before cloning. This affects undici versions from 7.24.1 up to 7.29.1 and from 8.0.0 up to 8.10.2, and only when the application supplies a function-valued connect or tls option to BalancedPool. Users should upgrade to undici 7.29.1 or 8.10.2.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

AV:N/PR:N/UI:N indica explotación remota sin autenticación. BalancedPool descarta callbacks TLS personalizados, permitiendo aceptar certificados rechazados, facilitando MITM. Afecta integridad de conexiones seguras.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Limit Access to Resource Over NetworkFilter Network TrafficEncrypt Sensitive InformationVulnerability ScanningUser TrainingPrivileged Account Management

Tecnologías afectadas (1)

Nodejs — Undici

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-84961",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-84961",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-04T18:35:57.858790Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.4,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 2.2
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.1,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "affectedData": [
        {
          "vendor": "undici",
          "product": "undici",
          "versions": [
            {
              "status": "affected",
              "version": "7.24.1",
              "lessThan": "7.29.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.29.1",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "8.0.0",
              "lessThan": "8.10.2",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "8.10.2",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:npm/undici",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-09-04T17:17:02.227",
  "references": [
    {
      "url": "https://cna.openjsf.org/security-advisories.html",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb"
    },
    {
      "url": "https://github.com/nodejs/undici/security/advisories/GHSA-w293-vg96-wgc3",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value as JSON. Because JSON cannot represent functions, any function-valued TLS option, such as a caller-supplied checkServerIdentity callback or a custom connector inside the connect option, is silently discarded before it reaches the TLS layer. As a result a peer whose certificate the application's custom checkServerIdentity was written to reject, but which still passes Node's default hostname and chain checks, is accepted when reached through BalancedPool. The Client, Pool, and Agent dispatchers are not affected because they extract the connect and tls options before cloning. This affects undici versions from 7.24.1 up to 7.29.1 and from 8.0.0 up to 8.10.2, and only when the application supplies a function-valued connect or tls option to BalancedPool. Users should upgrade to undici 7.29.1 or 8.10.2."
    }
  ],
  "lastModified": "2026-09-15T14:29:35.253",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "14C3FEF7-6460-4986-8FEB-A9F8540F14BA",
              "versionEndExcluding": "7.29.1",
              "versionStartIncluding": "7.24.1"
            },
            {
              "criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "848B6624-1708-4BF8-B9D7-8F34343D244B",
              "versionEndExcluding": "8.10.2",
              "versionStartIncluding": "8.0.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb"
}