CVE-2026-40347 — Uncontrolled Resource Consumption in Python-multipart

CWE-400 — Uncontrolled Resource ConsumptionCWE-834 — Excessive Iteration3 documents3 sources
Severity
5.3MEDIUMNVD
EPSS
0.0%
top 86.58%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
1
Kludex Python-multipart
Timeline
PublishedApr 18

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LExploitability: 3.9 | Impact: 1.4

Affected Packages2 packages

▶CVEListV5kludex/python-multipart< 0.0.26

🔴Vulnerability Details

2
VulDB
Kludex python-multipart up to 0.0.25 resource consumption (GHSA-mj87-hwqh-73pj / Nessus ID 307443)↗2026-04-18
▶
GHSA
python-multipart affected by Denial of Service via large multipart preamble or epilogue data↗2026-04-15
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