PyPI: aiohttp

CVE-2023-47641

Safety vulnerability ID: SFTY-20231114-21467

Safety legacy ID: pyup.io-62327

Aiohttp 3.8.0 includes a fix for CVE-2023-47641: Affected versions of aiohttp have a security vulnerability regarding the inconsistent interpretation of the http protocol. HTTP/1.1 is a persistent protocol, if both Content-Length(CL) and Transfer-Encoding(TE) header values are present it can lead to incorrect interpretation of two entities that parse the HTTP and we can poison other sockets with this incorrect interpretation. A possible Proof-of-Concept (POC) would be a configuration with a reverse proxy(frontend) that accepts both CL and TE headers and aiohttp as backend. As aiohttp parses anything with chunked, we can pass a chunked123 as TE, the frontend entity will ignore this header and will parse Content-Length. The impact of this vulnerability is that it is possible to bypass any proxy rule, poisoning sockets to other users like passing Authentication Headers, also if it is present an Open Redirect an attacker could combine it to redirect random users to another website and log the request. https://github.com/aio-libs/aiohttp/security/advisories/GHSA-xx9p-xxvh-7g8j

Created at: Jul 5, 2026Updated at: Jul 5, 2026

Overview

Aiohttp has inconsistent interpretation of `Content-Length` vs. `Transfer-Encoding` differing in C and Python fallbacks

Advisory

Aiohttp 3.8.0 includes a fix for CVE-2023-47641: Affected versions of aiohttp have a security vulnerability regarding the inconsistent interpretation of the http protocol. HTTP/1.1 is a persistent protocol, if both Content-Length(CL) and Transfer-Encoding(TE) header values are present it can lead to incorrect interpretation of two entities that parse the HTTP and we can poison other sockets with this incorrect interpretation. A possible Proof-of-Concept (POC) would be a configuration with a reverse proxy(frontend) that accepts both CL and TE headers and aiohttp as backend. As aiohttp parses anything with chunked, we can pass a chunked123 as TE, the frontend entity will ignore this header and will parse Content-Length. The impact of this vulnerability is that it is possible to bypass any proxy rule, poisoning sockets to other users like passing Authentication Headers, also if it is present an Open Redirect an attacker could combine it to redirect random users to another website and log the request. https://github.com/aio-libs/aiohttp/security/advisories/GHSA-xx9p-xxvh-7g8j

Affected Package

Affecting aiohttp package, versions<3.8.0

Also affects

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How to Fix

Upgradeaiohttpto3.8.0or higher.

Mitigation and Workarounds

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Vulnerable Functions

Functions linked to known vulnerabilities.

Vulnerable function data is available for Enterprise customers

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Safety

Verified by Safety

Our Cybersecurity Intelligence Team reviewed this vulnerability. We combine public data with our own research to find issues not yet reported to public sources.

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