This indicates an attack attempt to exploit an Integer Overflow vulnerability in Redis.
The vulnerability is due to improper checking in the application when handling malicious requests. A remote attacker may be able exploit this to execute arbitrary code within the context of the application via crafted requests.
Redis Labs Redis 2:2.8.17-1 and prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.