The issue concerns a Java Redis client that uses the Netty framework. Prior to version 3.22.0, some messages received from the Redis server contain Java objects that the client deserializes without further validation. Attackers can trick clients into communicating with a malicious server, including specially crafted objects in its responses that, once deserialized by the client, force it to execute arbitrary code. This can be abused to take control of the machine the client is running on.