CVE-2026-59870

MEDIUM 5.3

js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-407
Vendor	nodeca
Product	js-yaml
Published	Jul 8, 2026
Last Updated	Jul 8, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

nodeca / js-yaml

>= 5.0.0, < 5.2.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm github.com: https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe github.com: https://github.com/nodeca/js-yaml/releases/tag/5.2.1