High 7.5Published Jul 8, 2026

CVE-2026-59869js-yaml: YAML merge-key chains can force quadratic CPU consumption

Updated under an hour ago (Oct 26, 2026, 8:30 PM ET)

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Every CVE for nodeca js-yaml

Exploited in the last 30 days

js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-407
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

nodeca js-yaml nodeca:js_yaml (from the name)	from 3.0.0, < 3.15.0; from 4.0.0, < 4.3.0	CNA record
nodeca js-yaml nodeca:js-yaml	from 3.0.0 before 3.15.0; from 4.0.0 before 4.3.0	NVD

References

References

https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m	x-refsource-confirm, exploit, vendor-advisory
https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7	x-refsource-misc, patch
https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4	x-refsource-misc, patch
https://github.com/nodeca/js-yaml/releases/tag/3.15.0	x-refsource-misc, release-notes
https://github.com/nodeca/js-yaml/releases/tag/4.3.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.