Improper check or handling of exceptional conditions in MELSEC iQ-F series FX5U(C) CPU unit firmware version 1.060 and earlier allows an attacker to cause a denial-of-service (DoS) condition on program execution and communication by sending a specially crafted ARP packet.
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2020-018_en.pdf
https://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2020-018.pdf