An exploitable information exposure 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 an external tool to fail, resulting in uninitialized stack data to be copied to the response packet buffer. An attacker can send unauthenticated packets to trigger this vulnerability.