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Vulnerability record · CVE-2026-59870 · published 8 July 2026

CVE-2026-59870: Nodeca js-yaml allocation without limits vulnerability

Nodeca · Js Yaml

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.

7.5 CVSS 3.1 High EPSS 0.64% · top 51.2% CWE-407 · CWE-407CWE-770 · Allocation without limits
7.5CVSS 3.1 base score
0.64%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
10 Jul 2026Last modified by NVD

Description

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2026-59868Nodeca js-yaml allocation without limits vulnerabilityjs-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, js-yaml can spend quadratic CPU time parsing a …EPSS 0.64%7.5CVE-2026-59869Nodeca js-yaml vulnerabilityjs-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 …EPSS 0.59%6.8CVE-2013-4660Nodeca js-yaml improper input validation vulnerabilityThe JS-YAML module before 2.0.5 for Node.js parses input without properly considering the unsafe !!js/function tag, which allows remote attackers to …EPSS 17%5.3CVE-2026-53550Nodeca js-yaml vulnerabilityjs-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml …EPSS 0.42%5.3CVE-2025-64718Nodeca js-yaml prototype pollution vulnerabilityjs-yaml is a JavaScript YAML parser and dumper. In js-yaml before 4.1.1 and 3.14.2, it's possible for an attacker to modify the prototype of the resu…EPSS 0.41%

Source: NIST National Vulnerability Database (record CVE-2026-59870), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.