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CVE-2026-84375

Estado: AplazadaAlta (7.5)—

js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2, 4.3.2, and 5.4.1, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias a large sequence of empty mappings into many merge targets, causing O(N * K) processing while totalMergeKeys remains unchanged and the configured resource limit is never reached. A relatively small YAML document can therefore cause prolonged CPU consumption in applications that parse untrusted YAML, and merge processing is enabled by default on these release lines. In v3 & v4, merge is enabled by default so the severity score is higher. This issue is fixed in versions 3.15.2, 4.3.2, and 5.4.1.

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.

Acceso remoto sin autenticación (AV:N/PR:N/UI:N) contra aplicación YAML expuesta. La vulnerabilidad causa consumo intensivo de CPU mediante documentos YAML malformados, manifestándose como DoS de aplicación.

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

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Nodeca — Js-yamlAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-84375",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-84375",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-02T13:43:50.850378Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "nodeca",
          "product": "js-yaml",
          "versions": [
            {
              "status": "affected",
              "version": ">= 3.0.0, < 3.15.2"
            },
            {
              "status": "affected",
              "version": ">= 4.0.0, < 4.3.2"
            },
            {
              "status": "affected",
              "version": ">= 5.0.0, < 5.4.1"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-09-01T22:17:19.440",
  "references": [
    {
      "url": "https://github.com/nodeca/js-yaml/commit/3485bc06ff8a0251505f44a00414d90df2466639",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/commit/6a8e05f9a485188ed730ac81e81ae221352ef480",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/commit/d90b6612a5a84385bdcb556c44578eac76dc0f6b",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/pull/797",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/releases/tag/3.15.2",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/releases/tag/4.3.2",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/releases/tag/5.4.1",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-2883-xcg3-v3hh",
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2, 4.3.2, and 5.4.1, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias a large sequence of empty mappings into many merge targets, causing O(N * K) processing while totalMergeKeys remains unchanged and the configured resource limit is never reached. A relatively small YAML document can therefore cause prolonged CPU consumption in applications that parse untrusted YAML, and merge processing is enabled by default on these release lines. In v3 & v4, merge is enabled by default so the severity score is higher. This issue is fixed in versions 3.15.2, 4.3.2, and 5.4.1."
    }
  ],
  "lastModified": "2026-09-28T22:17:33.377",
  "sourceIdentifier": "security-advisories@github.com"
}