CVE-2023-37276: aiohttp vulnerable to HTTP request smuggling

Vulnerability summary

CVE-2023-37276 is a high (CVSS 7.5) vulnerability in aio-libs aiohttp. EPSS estimates a 1.34% chance of exploitation in the next 30 days, higher than 71.2% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 19-07-2023
   PublishedVulnerability first disclosed.
2. 18-10-2024
   Last modifiedVulnerability information updated.

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.

• CWE-444Inconsistent Interpretation of HTTP RequestsThe 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.