# CVE-2023-37276: python-aiohttp: aiohttp is an asynchronous HTTP client/server framework for asyncio and Python

CVE-2023-37276 is fixed in python-aiohttp on 1 platform, first by DEBIAN-CVE-2023-37276, released July 19, 2023. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2023-37276
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0134
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 19, 2023

## Description

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. aiohttp v3.8.4 and earlier are bundled with llhttp v6.0.6. Vulnerable code is used by aiohttp for its HTTP request parser when available which is the default case when installing from a wheel. This vulnerability only affects users of aiohttp as an HTTP server (ie `aiohttp.Application`), you are not affected by this vulnerability if you are using aiohttp as an HTTP client library (ie `aiohttp.ClientSession`). Sending a crafted HTTP request will cause the server to misinterpret one of the HTTP header values leading to HTTP request smuggling. This issue has been addressed in version 3.8.5. Users are advised to upgrade. Users unable to upgrade can reinstall aiohttp using `AIOHTTP_NO_EXTENSIONS=1` as an environment variable to disable the llhttp HTTP request parser implementation. The pure Python implementation isn't vulnerable.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-aiohttp Debian 13.5 (trixie) | 3.8.5-1 | [DEBIAN-CVE-2023-37276](https://patchblox.com/security/data/fix/linux/debian-cve-2023-37276.md) | Jul 19, 2023 |
| Linux | python-aiohttp Debian 14 | 3.8.5-1 | [DEBIAN-CVE-2023-37276](https://patchblox.com/security/data/fix/linux/debian-cve-2023-37276.md) | Jul 19, 2023 |

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