CVE-2026-40347Python-Multipart is a streaming multipart parser for Python.
Updated under an hour ago ()
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It affects fastapiexpert python-multipart. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Weakness (CWE)
- CWE-400, CWE-834
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
fastapiexpert python-multipart fastapiexpert:python-multipart | before 0.0.26 | NVD |
References
- https://github.com/Kludex/python-multipart/releases/tag/0.0.26product, release-notes
- https://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pjvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.