---
cve: "CVE-2026-86433"
severity: "HIGH"
cvss: 8.7
epss: "0.3%"
vendor: "thephpleague"
kev: false
exploited: false
published: "2026-09-07 13:20:42"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-22T08:06:52+02:00"
---

# CVE-2026-86433

> 8.7 HIGH · 🧪 PoC

## Beschreibung

commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Referenzen

- <https://github.com/thephpleague/commonmark/security/advisories/GHSA-g2gp-3wwq-f4ph>
- <https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-attributes>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-86433) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_