All versions of the afffected TOYOPUC-PC10 Series,TOYOPUC-Plus Series,TOYOPUC-PC3J/PC2J Series, TOYOPUC-Nano Series products may not be able to properly process an ICMP flood, which may allow an attacker to deny Ethernet communications between affected devices.

When JTEKT Corporation TOYOPUC PLC versions PC10G-CPU, 2PORT-EFR, Plus CPU, Plus EX, Plus EX2, Plus EFR, Plus EFR2, Plus 2P-EFR, PC10P-DP, PC10P-DP-IO, Plus BUS-EX, Nano 10GX, Nano 2ET,PC10PE, PC10PE-16/16P, PC10E, FL/ET-T-V2H, PC10B,PC10B-P, Nano CPU, PC10P, and PC10GE receive an invalid frame, the outside area of a receive buffer for FL-net are overwritten. As a result, the PLC CPU detects a system error, and the affected products stop.

If Ethernet communication of the JTEKT Corporation TOYOPUC product series’ (TOYOPUC-PC10 Series: PC10G-CPU TCC-6353: All versions, PC10GE TCC-6464: All versions, PC10P TCC-6372: All versions, PC10P-DP TCC-6726: All versions, PC10P-DP-IO TCC-6752: All versions, PC10B-P TCC-6373: All versions, PC10B TCC-1021: All versions, PC10B-E/C TCU-6521: All versions, PC10E TCC-4737: All versions; TOYOPUC-Plus Series: Plus CPU TCC-6740: All versions, Plus EX TCU-6741: All versions, Plus EX2 TCU-6858: All versions, Plus EFR TCU-6743: All versions, Plus EFR2 TCU-6859: All versions, Plus 2P-EFR TCU-6929: All versions, Plus BUS-EX TCU-6900: All versions; TOYOPUC-PC3J/PC2J Series: FL/ET-T-V2H THU-6289: All versions, 2PORT-EFR THU-6404: All versions) are left in an open state by an attacker, Ethernet communications cannot be established with other devices, depending on the settings of the link parameters.