CVE-2024-23829

aiohttp's HTTP parser (the python one, not llhttp) still overly lenient about separators

MEDIUM
6.5
CVSS Score
Published: January 29, 2024 at 10:41 PM UTC
Updated: June 17, 2026 at 07:13 AM UTC
3 products affected across 3 vendorsFedoraAiohttpAiohttp

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Severity
MEDIUM6.5
Exploit prediction
EPSS 1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.9.2
Affected range stops below 3.9.2, so it looks safe — our inference, not a vendor statement
v < 3.9.2
Affected range stops below 3.9.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-444

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