Useful in the context of aircraft cybersecurity to remember that the FAA has issued "Special Conditions" for a number of aircraft types equipped with "a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. This design feature is a digital systems architecture for the installation of a system with wireless network and hosted application functionality that allows access from external sources to the airplane’s internal electronic components."

This set of quotes come from FAA Special Conditions 2021-14974 published in the USA Federal Register on 14th July 2021.

Additional ... "This proposed network architecture is used for a diverse set of airplane functions, including: flight-safety related control and navigation systems; airline business and administrative support; passenger entertainment, and access by systems external to the airplane."

"The airplane-control domain and airline information-services domain of these networks perform functions required for the safe operation and maintenance of the airplane.
Previously, these domains had very limited connectivity with external network sources."

"This network architecture creates a potential for unauthorized persons to access the airplane-control domain and airline information-services domain from sources external to the airplane, and presents security vulnerabilities related to the introduction of computer viruses and worms, user errors, and intentional sabotage of airplane electronic assets (networks, systems, and databases) critical to the safety and maintenance of the airplane."

In summary - in the context of aircraft cybersecurity, it is useful to review the "Special Conditions" already issued by the FAA for a range of aircraft types.