CVE-2026-42561

high

Published 2026-05-13 · Modified 2026-05-14

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CVSS v3

7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4 NEW

—

not yet in upstream

VIR risk

7.5

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.

Predictions

Exploit likelihood

83%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

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OS impact

Debian Affected 5 releases

Version	Status	Fixed in
trixie	Affected	—
sid	Affected	—
forky	Affected	—
bullseye	Affected	—
bookworm	Affected	—

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

Package impact

Ecosystem	Package	Vulnerable	Fixed
PyPI	python-multipart	`<0.0.27`	`0.0.27`
PIP	python-multipart	`< 0.0.27`	`0.0.27`

References

CWEs

CWE-770

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.