CVE-2026-59869

HIGH

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

Title source: cna
STIX 2.1

Description

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.

References (5)

Core 5

Scores

CVSS v3 7.5
EPSS 0.0042
EPSS Percentile 34.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-407
Status published
Products (5)
nodeca/js-yaml 3.0.0 - 3.15.0
nodeca/js-yaml >= 3.0.0, < 3.15.0
nodeca/js-yaml >= 4.0.0, < 4.3.0
npm/js-yaml 3.0.0 - 3.15.0npm
npm/js-yaml 4.0.0 - 4.3.0npm
Published Jul 08, 2026
Tracked Since Jul 08, 2026