This indicates an attack attempt against an Integer Overflow vulnerability in Memcached.
The vulnerability is caused by an error when the vulnerable software handles multiple commands that prepend or append data. A remote unauthenticated attacker may be able to exploit this to execute arbitrary code in the context of the user.
Memcached Project Memcached prior to 1.4.33
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the latest update from the vendor.