CVE-2026-111750
Received Received - Intake

HTTP Request Smuggling in AIOHTTP Framework

Publication date: 2026-10-19

Last updated on: 2026-10-19

Assigner: GitHub, Inc.

Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.

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Meta Information

Published
2026-10-19
Last Modified
2026-10-19
Generated
2026-10-19
AI Q&A
2026-10-19
EPSS Evaluated
N/A
NVD
CVE-2026-111750
EUVD
EUVD-2026-104486

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
aio-libs aiohttp < 3.14.4

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-444 The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

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Executive Summary

This vulnerability is an HTTP request smuggling issue in the AIOHTTP library. It occurs because the pure Python parser in versions before 3.14.4 incorrectly handles ambiguous HTTP request framing. An attacker can exploit this to smuggle requests when the application runs without standard wheel extensions or with AIOHTTP_NO_EXTENSIONS enabled.

Detection Guidance

To detect this vulnerability, check if your aiohttp version is below 3.14.4. Run: pip show aiohttp. If using AIOHTTP_NO_EXTENSIONS, verify if the pure Python parser is active. Inspect HTTP traffic for ambiguous request framing patterns.

Impact Analysis

If you use AIOHTTP versions before 3.14.4 without the default C parser, an attacker could smuggle requests through your application. This may lead to cache poisoning, session hijacking, or bypassing security controls. The impact depends on how the intermediary systems interpret the malformed requests.

Mitigation Strategies

Upgrade aiohttp to version 3.14.4 or later. If using AIOHTTP_NO_EXTENSIONS, remove it to enable the default C parser. Monitor HTTP traffic for smuggling attempts and apply patches promptly.

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