CVE-2026-59868

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.

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-25)

CWEs

CWE-770, CWE-407

Published

2026-07-08

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Affected

• nodeca:js-yaml

Packages (OSV)

References

• https://github.com/nodeca/js-yaml/commit/3105455b81dee69e0fd36e09ac0b2ccfdb54adc1
• https://github.com/nodeca/js-yaml/releases/tag/5.2.0
• https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv
• https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv

Check your stackJSON