{"cve":"CVE-2026-73643","nvd":{"published":"2026-08-13T18:18:19.947","modified":"2026-10-24T15:10:00.190","status":"Deferred","description":"js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a flow-sequence entry is recognized as a key: value pair. If the key is a nested flow sequence of the same shape, every level is parsed twice, causing O(2^n) work and allowing an input under 200 bytes to keep one CPU busy for minutes, block the Node.js event loop, and stall the process. No anchors, aliases, merges, tags, or nondefault options are required. This issue is fixed in version 5.2.2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-407"],"references":["https://github.com/nodeca/js-yaml/commit/3e5240f9cbe645ce5afb58524954a13c8539c853","https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5","https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5"],"products":[],"source":"nvd","synced_at":"2026-10-24T16:53:35.584907681+00:00"},"epss":{"cve":"CVE-2026-73643","score":0.00488,"percentile":0.41695,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-pm4m-ph32-ghv5","url":"https://osv.dev/vulnerability/GHSA-pm4m-ph32-ghv5","summary":"js-yaml: Exponential parsing time in flow collections leads to denial of service","modified":"2026-09-10T03:51:11.652458936Z","packages":[{"ecosystem":"npm","name":"js-yaml","purl":"pkg:npm/js-yaml","ranges":[">=5.0.0 <5.2.2"],"fixed":["5.2.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}