EVAL is a Redis command that executes Lua scripts inside the Redis server process. Because the script runs server-side, it can read and modify data with the same trust and permissions as the database itself. That makes EVAL powerful for automation, but also security-sensitive: a bug in the script engine, a bad input check, or a memory-safety flaw in nearby code can have consequences far beyond a simple query failure.
In attacks, EVAL matters because it expands the code paths an attacker can reach after gaining access to a Redis instance. If an exploit chain already includes authenticated commands, server-side scripting may help shape or trigger deeper memory corruption and can increase the impact from denial of service to code execution in the Redis process. Defenders should treat EVAL as a privileged capability: restrict it with ACLs, limit network access, and patch quickly when scripting-related vulnerabilities appear.