This indicates an attack attempt to exploit a Denial of Service vulnerability in ISC BIND.
The vulnerability is caused by insufficient sanitizing of requests to rndc interface. A remote attacker may be able to exploit this to cause a denial of service condition on the affected system.
ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4
Denial of Service: Remote attackers can crash vulnerable systems or services
Apply the most recent upgrade or patch from the vendor.