Authentication Bypass by Capture-replay vulnerability in Mitsubishi Electric MELSEC iQ-F series FX5U(C) CPU all versions, Mitsubishi Electric MELSEC iQ-F series FX5UJ CPU all versions, Mitsubishi Electric MELSEC iQ-R series R00/01/02CPU all versions, Mitsubishi Electric MELSEC iQ-R series R04/08/16/32/120(EN)CPU all versions, Mitsubishi Electric MELSEC iQ-R series R08/16/32/120SFCPU all versions, Mitsubishi Electric MELSEC iQ-R series R08/16/32/120PCPU all versions, Mitsubishi Electric MELSEC iQ-R series R08/16/32/120PSFCPU all versions, Mitsubishi Electric MELSEC iQ-R series R16/32/64MTCPU all versions, Mitsubishi Electric MELSEC iQ-R series RJ71C24(-R2/R4) all versions, Mitsubishi Electric MELSEC iQ-R series RJ71EN71 all versions, Mitsubishi Electric MELSEC iQ-R series RJ72GF15-T2 all versions, Mitsubishi Electric MELSEC Q series Q03/04/06/13/26UDVCPU all versions, Mitsubishi Electric MELSEC Q series Q04/06/13/26UDPVCPU all versions, Mitsubishi Electric MELSEC Q series QJ71C24N(-R2/R4) all versions and Mitsubishi Electric MELSEC Q series QJ71E71-100 all versions allows a remote unauthenticated attacker to login to the product by replay attack.
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-031_en.pdf