In netty-codec-redis versions prior to 4.1.135.Final and 4.2.15.Final, an attacker can cause a denial of service (DoS) by sending specially crafted Redis payloads across multiple connections without proper line termination. This triggers exhaustion of the server's direct memory pool, resulting in an OutOfDirectMemoryError and preventing legitimate connections from being processed. The issue is patched in versions 4.1.135.Final and 4.2.15.Final.