aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Improper validation made it possible for an attacker to modify the HTTP request (e.g. to insert a new header) or create a new HTTP request if the attacker controls the HTTP version. The vulnerability only occurs if the attacker can control the HTTP version of the request. This issue has been patched in version 3.9.0.
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-q3qx-c6g2-7pw2
https://github.com/aio-libs/aiohttp/pull/7835/files
https://github.com/aio-libs/aiohttp/commit/1e86b777e61cf4eefc7d92fa57fa19dcc676013b
https://gist.github.com/jnovikov/184afb593d9c2114d77f508e0ccd508e