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FKIE_CVE-2026-84375

Vulnerability from fkie_nvd - Published: 2026-09-01 22:17 - Updated: 2026-09-09 21:09
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2 and 4.3.2, 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. This issue is fixed in versions 3.15.2 and 4.3.2.
References
security-advisories@github.comhttps://github.com/nodeca/js-yaml/commit/3485bc06ff8a0251505f44a00414d90df2466639
security-advisories@github.comhttps://github.com/nodeca/js-yaml/commit/6a8e05f9a485188ed730ac81e81ae221352ef480
security-advisories@github.comhttps://github.com/nodeca/js-yaml/commit/d90b6612a5a84385bdcb556c44578eac76dc0f6b
security-advisories@github.comhttps://github.com/nodeca/js-yaml/pull/797
security-advisories@github.comhttps://github.com/nodeca/js-yaml/releases/tag/3.15.2
security-advisories@github.comhttps://github.com/nodeca/js-yaml/releases/tag/4.3.2
security-advisories@github.comhttps://github.com/nodeca/js-yaml/security/advisories/GHSA-2883-xcg3-v3hh
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "js-yaml",
          "vendor": "nodeca",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.15.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 4.3.2"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2 and 4.3.2, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key \u003c\u003c. 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. This issue is fixed in versions 3.15.2 and 4.3.2."
    }
  ],
  "id": "CVE-2026-84375",
  "lastModified": "2026-09-09T21:09:13.080",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-84375",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-02T13:43:50.850378Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-01T22:17:19.440",
  "references": [
    {
      "source": "security-advisories@github.com",
      "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/security/advisories/GHSA-2883-xcg3-v3hh"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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