Threat surface

Each interface, port, wireless link and software update path adds to the threat surface. Removing interfaces that are not needed is one of the most direct ways to lower cybersecurity risk.

the set of points on the boundary of a system, a system element, or an environment where a cyber threat can try to enter, cause an effect on, or extract data from, that system, system element, or environment.

FDA guidance: Cybersecurity in Medical Devices: Quality Management System Considerations and Content of Premarket Submissions (February 2026), Appendix 5, Terminology