CVE-2026-59869: Nodeca Js-Yaml

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 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.

Affected products

• Nodeca Js-Yaml: from 3.0.0, before 3.15.0 (fixed in 3.15.0); from 4.0.0, before 4.3.0 (fixed in 4.3.0)

Published 2026-07-08. Last modified 2026-07-13.