CVE-2026-53540
Python-Multipart: Negative Content-Length in parse_form buffers the entire body in memory
CVSS Score
3.7
EPSS Score
0.0%
EPSS Percentile
0th
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.31, parse_form() did not validate the Content-Length header before using it to bound its chunked read of the request body. A negative Content-Length turned the bounded read into a read-until-EOF, so the entire body was loaded into memory in a single read instead of in fixed-size chunks. This vulnerability is fixed in 0.0.31.
| CWE | CWE-1284 |
| Vendor | kludex |
| Product | python-multipart |
| Published | Jun 22, 2026 |
| Last Updated | Jun 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
Kludex / python-multipart
< 0.0.31