CVE-2026-28356
Publication date 12 March 2026
Last updated 2 June 2026
Ubuntu priority
Description
multipart is a fast multipart/form-data parser for python. Prior to 1.2.2, 1.3.1 and 1.4.0-dev, the parse_options_header() function in multipart.py uses a regular expression with an ambiguous alternation, which can cause exponential backtracking (ReDoS) when parsing maliciously crafted HTTP or multipart segment headers. This can be abused for denial of service (DoS) attacks against web applications using this library to parse request headers or multipart/form-data streams. The issue is fixed in 1.2.2, 1.3.1 and 1.4.0-dev.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| multipart | 26.04 LTS resolute |
Fixed 1.3.0-3ubuntu0.1
|
| 25.10 questing |
Fixed 1.2.1-2+deb13u1build0.25.10.1
|
|
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release |
Severity score breakdown
CVSS version: CVSS v3.0
Base score
7.5 · High
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8343-1
- multipart vulnerability
- 28 May 2026