An exploitable command injection vulnerability exists in the iocheckd service ‘I/O-Check’ function of the WAGO PFC 200 version 03.02.02(14). A specially crafted XML cache file written to a specific location on the device can be used to inject OS commands. An attacker can send a specially crafted packet to trigger the parsing of this cache file.At 0x1e9fc the extracted subnetmask value from the xml file is used as an argument to /etc/config-tools/config_interfaces interface=X1 state=enabled subnet-mask=<contents of subnetmask node> using sprintf(). This command is later executed via a call to system().