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.

Scoring

Severity
MEDIUM
CVSS base score
5.3
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS probability
0.35%
CWE
CWE-400, CWE-834
Published
2026-04-17
Last modified
2026-04-20

Affected products

Weakness type

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