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