AIOHTTP vulnerable to DoS when bypassing asserts

Summary

When assert statements are bypassed, an infinite loop can occur, resulting in a DoS attack when processing a POST body.

Impact

If optimisations are enabled (-O or PYTHONOPTIMIZE=1), and the application includes a handler that uses the Request.post() method, then an attacker may be able to execute a DoS attack with a specially crafted message.

Patch: https://github.com/aio-libs/aiohttp/commit/bc1319ec3cbff9438a758951a30907b072561259