This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Firebird SQL Server.
The vulnerability is due to an error when the vulnerable software handles a maliciously 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.
Firebird SQL Server 2.1.3-2.1.5
Firebird SQL Server 2.5.0-2.5.2
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.