Bug 2262843 (CVE-2024-24762)

Summary:	CVE-2024-24762 python-fastapi: regular expression denial of service vulnerability
Product:	[Other] Security Response	Reporter:	Robb Gatica <rgatica>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	Keywords:	Security
Target Milestone:	---
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Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	fastapi 0.109.0	Doc Type:	---
Doc Text:	A flaw was discovered in the FastAPI framework. 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. This can cause the main event loop to stall indefinitely, which can lead to a denial of service.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2262844
Bug Blocks:

Description Robb Gatica 2024-02-05 17:52:03 UTC

FastAPI is a web framework for building APIs with Python 3.8+ based on standard Python type hints. 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. It's a ReDoS(Regular expression Denial of Service), it only applies to those reading form data, using `python-multipart`. This vulnerability has been patched in version 0.109.0.

https://github.com/tiangolo/fastapi/commit/9d34ad0ee8a0dfbbcce06f76c2d5d851085024fc
https://github.com/tiangolo/fastapi/releases/tag/0.109.1
https://github.com/tiangolo/fastapi/security/advisories/GHSA-qf9m-vfgh-m389

Comment 1 Robb Gatica 2024-02-05 17:52:16 UTC

Created python-fastapi tracking bugs for this issue:

Affects: fedora-all [bug 2262844]