CVE-2026-42561
Python-Multipart: Denial of Service via unbounded multipart part headers
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-770 |
| Vendor | kludex |
| Product | python-multipart |
| Published | May 13, 2026 |
Stay Ahead of the Next One
Get instant alerts for kludex python-multipart
Be the first to know when new high vulnerabilities affecting kludex python-multipart are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Kludex / python-multipart
< 0.0.27