Redis is an in-memory data structure store. In all versions of redis-server with Lua scripting, an authenticated attacker can exploit the master-replica synchronization mechanism to trigger a use-after-free on replicas where replica-read-only is disabled or can be disabled, which may lead to remote code execution. A workaround is to prevent users from executing Lua scripts or avoid using replicas where replica-read-only is disabled. This is patched in version 8.6.3.