CVE-2026-40347

Name	CVE-2026-40347
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
python-multipart (PTS)	bullseye	0.0.5-2	vulnerable
	bookworm	0.0.5-3	vulnerable
	trixie	0.0.20-1.1~deb13u1	vulnerable
	forky	0.0.22-1	vulnerable
	sid	0.0.26-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-multipart	source	(unstable)	0.0.26-1

Notes

https://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj
https://github.com/Kludex/python-multipart/pull/259
Fixed by: https://github.com/Kludex/python-multipart/commit/d4452a78bbde94995dd3c0d1b4aff3610a5c472f (0.0.26)