CVE-2026-59869

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.

Score

CVSS 3.1 7.5 High

Status

Analyzed - security-advisories@github.com

Published

2026-07-08

Last modified

2026-10-25

Weaknesses

CWE-407

Affected products

• Js-yaml (Nodeca)

References

• https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m
• https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7
• https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4
• https://github.com/nodeca/js-yaml/releases/tag/3.15.0
• https://github.com/nodeca/js-yaml/releases/tag/4.3.0