kafka-python vulnerable to denial of service through an unvalidated protocol frame length

kafka-python prior to 2.3.2 contains a denial-of-service vulnerability in the protocol parser that allows a malicious broker or machine-in-the-middle attacker to exhaust memory or hang connections by sending a crafted 4-byte frame length value without bounds validation. Attackers can send a specially crafted frame length through the receive_bytes() function to trigger either a multi-gigabyte memory allocation or an uncaught ValueError that leaves the connection in a broken state, causing requests to hang and consumers to stop heartbeating until restart.