{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "3.15.0"
              },
              {
                "introduced": "4.0.0"
              },
              {
                "fixed": "4.2.0"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "c34b6c40027a769eb0d67958ae615268a1d55f54"
            },
            {
              "introduced": "ee74ce4b4800282b2f23b776be7dc95dfe34db1c"
            },
            {
              "fixed": "590dbabadd172b099c07654fab2eabec8c7a07b9"
            }
          ],
          "repo": "https://github.com/nodeca/js-yaml",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-h67p-54hq-rp68"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-407"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53550.json"
  },
  "details": "js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (\u003c\u003c) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.",
  "id": "CVE-2026-53550",
  "modified": "2026-07-11T03:53:36.545917696Z",
  "published": "2026-06-22T14:59:14.906Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53550.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-h67p-54hq-rp68"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53550"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases"
}