---
cve: "CVE-2026-40347"
severity: "MEDIUM"
cvss: 5.3
epss: "35%"
vendor: "Kludex"
kev: false
exploited: false
published: "2026-04-18 00:16:38"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-12T12:13:38+02:00"
---

# CVE-2026-40347

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

Python-Multipart is a streaming multipart parser for Python. Versions prior to 0.0.26 have a denial of service vulnerability when parsing crafted `multipart/form-data` requests with large preamble or epilogue sections. Upgrade to version 0.0.26 or later, which skips ahead to the next boundary candidate when processing leading CR/LF data and immediately discards epilogue data after the closing boundary.

## 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)

- 28f47859b4a40c2e11e02dc514b2e9743ceedd2e (Commit)

## Referenzen

- <https://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj>
- <https://github.com/Kludex/python-multipart/releases/tag/0.0.26>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-40347) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_