GHSA-MH29-5H37-FV8M

Vulnerability from github – Published: 2025-11-14 14:29 – Updated: 2026-01-31 03:32
VLAI
Summary
js-yaml has prototype pollution in merge (<<)
Details

Impact

In js-yaml 4.1.0, 4.0.0, and 3.14.1 and below, it's possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (__proto__). All users who parse untrusted yaml documents may be impacted.

Patches

Problem is patched in js-yaml 4.1.1 and 3.14.2.

Workarounds

You can protect against this kind of attack on the server by using node --disable-proto=delete or deno (in Deno, pollution protection is on by default).

References

https://cheatsheetseries.owasp.org/cheatsheets/Prototype_Pollution_Prevention_Cheat_Sheet.html

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "js-yaml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "js-yaml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.14.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-64718"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-11-14T14:29:48Z",
    "nvd_published_at": "2025-11-13T16:15:57Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nIn js-yaml 4.1.0, 4.0.0, and 3.14.1 and below, it\u0027s possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (`__proto__`). All users who parse untrusted yaml documents may be impacted.\n\n### Patches\n\nProblem is patched in js-yaml 4.1.1 and 3.14.2.\n\n### Workarounds\n\nYou can protect against this kind of attack on the server by using `node --disable-proto=delete` or `deno` (in Deno, pollution protection is on by default).\n\n### References\n\nhttps://cheatsheetseries.owasp.org/cheatsheets/Prototype_Pollution_Prevention_Cheat_Sheet.html",
  "id": "GHSA-mh29-5h37-fv8m",
  "modified": "2026-01-31T03:32:42Z",
  "published": "2025-11-14T14:29:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-mh29-5h37-fv8m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-64718"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/js-yaml/issues/730#issuecomment-3549635876"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/js-yaml/commit/383665ff4248ec2192d1274e934462bb30426879"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/js-yaml/commit/5278870a17454fe8621dbd8c445c412529525266"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-mh29-5h37-fv8m"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nodeca/js-yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "js-yaml has prototype pollution in merge (\u003c\u003c)"
}


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