This indicates an attack attempt to exploit a Denial of Service vulnerability in the InnoDB memcached plugin component of Oracle MySQL Server.
The vulnerability is due to an error when the vulnerable software handles certain types of requests. By sending a large number of a certain type of command to a targeted server, a remote attacker can crash the vulnerable server.
Oracle MySQL 5.6.x prior to 5.6.11
Denial of Service: Remote attackers can crash vulnerable systems.
Apply patch, available from the vendor's website.