kafka-python prior to 2.3.2 contains a denial-of-service vulnerability in SCRAM authentication handling that allows a malicious or machine-in-the-middle broker to freeze the client event loop by supplying an excessively large iteration count. In scram.py, ScramClient.process_server_first_message() passes the broker-controlled SCRAM iteration count directly to hashlib.pbkdf2_hmac() without validation, blocking producer sends, consumer polls, admin operations, and heartbeats, which can cause consumer group eviction and repeated reconnect failures.
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.