CVE-2024-23829 MEDIUM

CVE-2024-23829: aiohttp's HTTP parser (the python one, not llhttp) still overly lenient about separators

Vendor Aio-Libs
Product aiohttp
Weakness CWE-444
Published January 29, 2024
Last update November 3, 2025

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity Low

CVSS vector

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

What the vulnerability does

Description

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Security-sensitive parts of the Python HTTP parser retained minor differences in allowable character sets, that must trigger error handling to robustly match frame boundaries of proxies in order to protect against injection of additional requests. Additionally, validation could trigger exceptions that were not handled consistently with processing of other malformed input. Being more lenient than internet standards require could, depending on deployment environment, assist in request smuggling. The unhandled exception could cause excessive resource consumption on the application server and/or its logging facilities. This vulnerability exists due to an incomplete fix for CVE-2023-47627. Version 3.9.2 fixes this vulnerability.

Key dates

Disclosure timeline

January 29, 2024 CVE published
November 3, 2025 Record updated