{"id":"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.","aliases":["GHSA-724g-mxrg-4qvm"],"modified":"2026-07-12T04:03:13.016099833Z","published":"2026-07-08T15:13:20.308Z","database_specific":{"cwe_ids":["CWE-407"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59870.json","cna_assigner":"GitHub_M"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nodeca/js-yaml","events":[{"introduced":"75148bc4f5eb69b3d338e1c355d8bb2dba5bdf34"},{"fixed":"ac16b42c46c11c5c7f66062bfc78b168b5f07ecd"},{"fixed":"39f3211a2f01b3c6982710cf21434ab7060acefe"}],"database_specific":{"extracted_events":[{"introduced":"5.0.0"},{"fixed":"5.2.1"}],"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*"}}],"versions":["5.2.0","5.1.0","5.0.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-59870.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}