# CVE-2026-40347

> Vulnerability · severity: **MEDIUM** (CVSS 5.3).

## Description

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.

## Key facts

- **CVE ID:** CVE-2026-40347
- **Published:** 2026-04-18
- **CVSS severity:** MEDIUM
- **CVSS base score:** 5.3
- **CWE codes:** CWE-400, CWE-834

## Affected products

- `fastapiexpert:python-multipart`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40347

## Citation

> AI Analytics. CVE-2026-40347. Retrieved 2026-07-15 from https://api.ai-analytics.org/cve/CVE-2026-40347. Derived from NIST NVD. Licensed CC0.

---

*[Dataset catalog](https://api.ai-analytics.org/datasets/) · [AI Analytics](https://api.ai-analytics.org/) · CC0 1.0*