Description
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.
References10
- github.com/Kludex/python-multipart/security/advisories/GHSA-pp6…
- access.redhat.com/errata/RHSA-2026:37275
- access.redhat.com/errata/RHSA-2026:42132
- access.redhat.com/errata/RHSA-2026:42142
- access.redhat.com/errata/RHSA-2026:43038
- access.redhat.com/errata/RHSA-2026:44696
- access.redhat.com/errata/RHSA-2026:51194
- access.redhat.com/errata/RHSA-2026:51219
- access.redhat.com/errata/RHSA-2026:51357
- access.redhat.com/security/cve/CVE-2026-42561
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 55 · as of 14 November 2026
- CWE
- CWE-770CWE-606
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.