---
cve: "CVE-2026-59870"
severity: "MEDIUM"
cvss: 5.3
epss: "0.6%"
vendor: "nodeca"
kev: false
exploited: false
published: "2026-07-08 16:16:33"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-20T21:45:22+02:00"
---

# CVE-2026-59870

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Gering | warn |

## Patch verfügbar (OSV)

- ac16b42c46c11c5c7f66062bfc78b168b5f07ecd (Commit)
- 39f3211a2f01b3c6982710cf21434ab7060acefe (Commit)

## Referenzen

- <https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm>
- <https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe>
- <https://github.com/nodeca/js-yaml/releases/tag/5.2.1>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-59870) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_