Denial of Service Vulnerability in Python-Multipart by Kludex
CVE-2026-42561

7.5HIGH

Key Information:

Vendor

Kludex

Status
Python-multipart
Vendor
CVE Published:
13 May 2026

What is CVE-2026-42561?

Python-Multipart, a streaming multipart parser for Python, has a vulnerability that can lead to denial of service during the parsing of multipart/form-data. Versions prior to 0.0.27 allow an attacker to exploit the parser by sending numerous repeated headers or a single excessively large header value, which exhausts CPU resources during processing. This can either lead to delayed request processing or a failure to process requests altogether. The issue has been addressed in version 0.0.27.

Affected Version(s)

python-multipart < 0.0.27

References

https://github.com/Kludex/python-multipart/security/advis...
x_refsource_CONFIRM

CVSS V3.1

Score:
7.5
Severity:
HIGH
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

.