CVE-2026-59868

FAUCET Score

js-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 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 version 5.2.0.

First published: Jul 8, 2026Last modified: Jul 8, 2026

Impacted Technologies

Vendor	Product	Version(s)	CPE
		>= 5.0.0, < 5.2.0CPE matchmatch criteria	cpe:2.3:a:nodeca:js-yaml::::::node.js::*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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 Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

Exploitability Score

3.9

Impact Score

1.4

CvssVersion

3.1

Exploit Intelligence

EPSS Score

0.41%

Probability of exploitation in next 30 days

EPSS Percentile

33.5%

Percentile rank of EPSS score among Peer Group

As of 2026-07-27

Model: v2026.06.15

This CVE's current EPSS score of 0.0041 is in the 13th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

npmpatch availablevia ghsa

Product: js-yamlFixed in: 5.2.0

Vendor Advisories (1)

npmGHSA-g796-fgmg-93mvmedium

js-yaml: YAML merge-key chains can force quadratic CPU consumption in js-yaml

Jul 20, 2026

References

github.com / nodeca/js-yaml/commit/3105455b81dee69e0fd36e09ac0b2ccfdb54adc1

Patch

github.com / nodeca/js-yaml/releases/tag/5.2.0

Release Notes

github.com / nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv

ExploitVendor Advisory