Snes9K version 0.0.9z contains a critical buffer overflow vulnerability in the Netplay Socket Port Number field. The vulnerability allows local attackers to trigger a structured exception handler (SEH) overwrite by crafting malicious payloads. Attackers can paste the payload into the Socket Port Number field through the Netplay Options menu. The vulnerability enables code execution through SEH chain exploitation. This represents a significant security risk for users of the affected gaming emulator software.