CVE-2026-59870

Name	CVE-2026-59870
Description	js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. This issue is fixed in version 5.2.1.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
node-js-yaml (PTS)	bullseye	3.14.1+dfsg+~3.12.6-2	fixed
	bookworm, trixie	4.1.0+dfsg+~4.0.5-7	fixed
	forky, sid	4.2.0+~4.0.9-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
node-js-yaml	source	(unstable)	(not affected)

Notes

- node-js-yaml <not-affected> (Vulnerable code not present)
https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm
Fixed by: https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe (5.2.1)