This indicates an attack attempt against a Stack Buffer Overflow vulnerability in PostgreSQL database server.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application when handling a crafted request. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted request to the vulnerable service.
PostgreSQL PostgreSQL prior to 8.4.20
PostgreSQL PostgreSQL prior to 9.0.16
PostgreSQL PostgreSQL prior to 9.1.12
PostgreSQL PostgreSQL prior to 9.2.7
PostgreSQL PostgreSQL prior to 9.3.3
System Compromise: Remote attackers can execute arbitrary code in the context of the affected application.
Apply the most recent upgrade or patch from the vendor.