---
cve: "CVE-2026-86250"
severity: "HIGH"
cvss: 7.5
epss: "26.6%"
vendor: "Generic Security"
kev: false
exploited: false
published: "2026-09-06 12:17:15"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-06T20:04:41+02:00"
---

# CVE-2026-86250

> 7.5 HIGH

## Beschreibung

h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() functions. Attackers can send a crafted cookie header with an extremely large chunk count to trigger an O(n²) cleanup loop that hangs the server process.

## CVSS-Vektor

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

| 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 | Hoch | bad |

## Referenzen

- <https://github.com/h3js/h3/security/advisories/GHSA-q5pr-72pq-83v3>
- <https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-denial-of-service-via-unbounded-chunked-cookie>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-86250) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_