CVE-2026-40347

MEDIUM

Python-Multipart affected by Denial of Service via large multipart preamble or epilogue data

Title source: cna
STIX 2.1

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.

References (2)

Core 2

Scores

CVSS v3 5.3
EPSS 0.0035
EPSS Percentile 26.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-400 CWE-834
Status published
Products (2)
Kludex/python-multipart < 0.0.26
pypi/python-multipart 0 - 0.0.26PyPI
Published Apr 18, 2026
Tracked Since Apr 18, 2026