{"id":"CVE-2026-53550","revision":"1d906a8f93144f44b1dbfcf0db213eb5","records":[{"revision":"1d906a8f93144f44b1dbfcf0db213eb5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-53550","aliases":[],"title":"js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases","description":"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 (<<) 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.","state":0,"publishedAt":"2026-06-22T14:59:14.906+00:00","modifiedAt":"2026-06-29T15:06:58.346+00:00","affected":[{"ecosystem":"Vendor product","name":"js-yaml","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"nodeca\",\n                    \"product\": \"js-yaml\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 4.0.0, < 4.2.0\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"< 3.15.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3,"severity":"MEDIUM"}],"references":["https://github.com/nodeca/js-yaml/security/advisories/GHSA-h67p-54hq-rp68"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-53550","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-53550","identifiers":["CVE-2026-53550"]},"retained":false,"historicalAffected":[]}],"coverage":[]}