{"id":"CVE-2026-59870","aliases":["GHSA-724g-mxrg-4qvm"],"url":"https://o3.security/vulnerability/CVE-2026-59870","summary":"js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing","details":"js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. This issue is fixed in version 5.2.1.","published":"2026-07-08T15:13:20.308Z","modified":"2026-08-12T03:51:10.551847695Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"js-yaml","fixedVersion":"5.2.1"}],"fix":{"url":"https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe","label":"nodeca/js-yaml@39f3211"},"references":[{"type":"WEB","url":"https://github.com/nodeca/js-yaml/releases/tag/5.2.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59870.json"},{"type":"ADVISORY","url":"https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59870"},{"type":"FIX","url":"https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:10.551847695Z"}}