Vulnerability Advisory : AIOHTTP: Pure-Python parser request replay and buffer growth behind a declined upgrade with LOW Attack Complexity

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, when the pipelined request queue is full, the pure-Python parser stores the unparsed remainder internally and also returns the same data to its caller. After a handler declines an upgrade request, the caller feeds the remainder back to the parser, causing the buffer to grow with each handled request and dispatching already-handled requests to the application again. The issue affects deployments using AIOHTTP_NO_EXTENSIONS or otherwise running without the standard C-extension wheel, and can cause excessive memory use and repeated request processing. This issue is fixed in version 3.14.4.