An exploitable heap buffer overflow vulnerability exists in the iocheckd service "I/O-Check" functionality 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 can cause a heap buffer overflow, potentially resulting in code execution. An attacker can send unauthenticated packets to trigger this vulnerability.