Missing Authentication for Critical Function vulnerability in Mitsubishi Electric Corporation G-50 Version 3.37 and prior, G-50-W Version 3.37 and prior, G-50A Version 3.37 and prior, GB-50 Version 3.37 and prior, GB-50A Version 3.37 and prior, GB-24A Version 9.12 and prior, G-150AD Version 3.21 and prior, AG-150A-A Version 3.21 and prior, AG-150A-J Version 3.21 and prior, GB-50AD Version 3.21 and prior, GB-50ADA-A Version 3.21 and prior, GB-50ADA-J Version 3.21 and prior, EB-50GU-A Version 7.11 and prior, EB-50GU-J Version 7.11 and prior, AE-200J Version 8.01 and prior, AE-200A Version 8.01 and prior, AE-200E Version 8.01 and prior, AE-50J Version 8.01 and prior, AE-50A Version 8.01 and prior, AE-50E Version 8.01 and prior, EW-50J Version 8.01 and prior, EW-50A Version 8.01 and prior, EW-50E Version 8.01 and prior, TE-200A Version 8.01 and prior, TE-50A Version 8.01 and prior, TW-50A Version 8.01 and prior, and CMS-RMD-J Version 1.40 and prior allows a remote unauthenticated attacker to bypass authentication and then control the air conditioning systems illegally, or disclose information in them by exploiting this vulnerability. In addition, the attacker may tamper with firmware for them using the disclosed information.