CVE-2026-40347

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 v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/Kludex/python-multipart/releases/tag/0.0.26	Product Release Notes
https://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:fastapiexpert:python-multipart:*:*:*:*:*:python:*:*

History

No history.

Information

Published : 2026-04-18 00:16

Updated : 2026-06-17 10:45

NVD link : CVE-2026-40347

Mitre link : CVE-2026-40347

CVE.ORG link : CVE-2026-40347

JSON object : View

Products Affected

fastapiexpert

python-multipart

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-834

Excessive Iteration

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