CVE-2026-59870 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-59870HIGH

nodeca js-yaml — js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  N  N  H    7.5   .0041   34.3     —

AFFECTED
  Product  Versions             Fixed
  js-yaml  >= 5.0.0, < 5.2.1 –  —

TIMELINE
  Jul 7   Reserved by GitHub_M
  Jul 8   EXPLOIT PUBLISHED — CVE-2026-59870 (nodeca js-yaml). Public exploit reference added.
  Jul 8   Published (CNA: GitHub_M)

CWE-770, CWE-407 · CNA: GitHub_M · CVSS v3.1 · 3 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
July 7, 2026	Reserved	Reserved by GitHub_M
July 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-59870 (nodeca js-yaml). Public exploit reference added.
July 8, 2026	Published	Published (CNA: GitHub_M)

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
nodeca	js-yaml	—	>= 5.0.0, < 5.2.1	—

Weaknesses

CWE-770 · CWE-407

References (3)

https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe [Patch]
https://github.com/nodeca/js-yaml/releases/tag/5.2.1 [Release Notes]
https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-59870 at cve.org

Vendors: nodeca

Weaknesses: CWE-770 · CWE-407

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59870 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.