CVE-2026-42561
HIGH7.5EPSS 0.07%python-multipart has Denial of Service via unbounded multipart part headers
Published: 5/6/2026Modified: 5/14/2026
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.
Affected packages (2)
- Debian/python-multipartfrom 0
- PyPI/python-multipartfrom 0, < 0.0.27
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |