Tornado: Event loop blocking and excess memory use from chunked bodies with many small chunks

Summary When Tornado reads an HTTP/1.1 body that uses chunked transfer encoding, it processes all chunks that have already arrived without yielding to the event loop. A client can send a body made of millions of 1-byte chunks, which blocks the event loop and therefore every other connection serve...

CVE-2026-115927 Tornado: Event loop blocking and excess memory use from chunked bodies with many small chunks

Tornado is a Python web framework and asynchronous networking library. Prior to 6.6.0, Tornado decodes HTTP/1.1 chunked transfer encoding by processing body data that has already arrived without yielding to the event loop. A remote unauthenticated peer can send millions of one-byte chunks to...