An exploitable stack buffer overflow vulnerability exists in the command line utility getcouplerdetails of WAGO PFC200 Firmware versions 03.01.07(13) and 03.00.39(12) and WAGO PFC100 Firmware version 03.00.39(12). A specially crafted set of packets sent to the iocheckd service \I/O-Check\ can cause a stack buffer overflow in the sub-process getcouplerdetails resulting in code execution. An attacker can send unauthenticated packets to trigger this vulnerability.