GHSA-3f84-rpwh-47g6

Waitress vulnerable to DoS leading to high CPU usage/resource exhaustion

### Impact When a remote client closes the connection before waitress has had the opportunity to call `getpeername()` waitress won't correctly clean up the connection leading to the main thread attempting to write to a socket that no longer exists, but not removing it from the list of sockets to attempt to process. This leads to a busy-loop calling the write function. A remote attacker could run waitress out of available sockets with very little resources required. ### Patches Waitress 3.0.1 contains fixes that remove the race condition. ### Workarounds No work-around. ### References - https://github.com/Pylons/waitress/issues/418 - https://github.com/Pylons/waitress/pull/435