Denial of Service Vulnerability in Python-Multipart by Kludex
CVE-2026-40347

5.3MEDIUM

Key Information:

Vendor

Kludex

Status
Python-multipart
Vendor
CVE Published:
17 April 2026

What is CVE-2026-40347?

The Python-Multipart library, designed for parsing multipart data in Python applications, has a vulnerability that could lead to denial of service. Specifically, versions earlier than 0.0.26 are at risk when handling specially crafted multipart/form-data requests containing large preamble or epilogue sections. Attackers can exploit this vulnerability to disrupt service by sending carefully crafted data. To mitigate this issue, it's crucial for users to upgrade to version 0.0.26 or later, as the update improves the handling of leading CR/LF data and ensures epilogue data is effectively discarded post-processing.

Affected Version(s)

python-multipart < 0.0.26

References

https://github.com/Kludex/python-multipart/security/advis...
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https://github.com/Kludex/python-multipart/releases/tag/0...
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CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.