CVE-2026-40347
MEDIUM5.3EPSS 0.02%python-multipart affected by Denial of Service via large multipart preamble or epilogue data
Published: 4/15/2026Modified: 6/2/2026
Also known as:DEBIAN-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.
Affected packages (2)
- Debian/python-multipartfrom 0
- PyPI/python-multipartfrom 0, < 0.0.26
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
References (5)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-40347
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-40347
- PATCHhttps://github.com/Kludex/python-multipart
- WEBhttps://github.com/Kludex/python-multipart/releases/tag/0.0.26
- WEBhttps://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj