This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Heroes of Might and Magic III.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted .H3M file. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted .H3M file.
HoMM3 H3 Complete 126.96.36.199
HoMM3 HD Mod 3.808 build 9
HoMM3 Heroes III Demo 188.8.131.52
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently we are unaware of any vendor supplied patch for this issue.