CVE-2026-59870
js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing
HIGH 7.5EPSS 0.7%
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.
- Affected
- nodeca · js-yaml
- CVSS v3.1 NVD
- 7.5 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS v3.1 GitHub
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS
- 0.74% chance of exploitation in the next 30 days, 54th percentile
- Published
- 2026-07-08
- Updated
- 2026-10-06
Proof-of-concept exploits (1)
Security advisories
- nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm
- nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe