A CGI program is a web-handling component that receives HTTP requests and turns them into actions on a device. In embedded systems such as switches, routers, and cameras, it often powers the admin interface used to view status, change settings, or submit forms. Even though it looks like a simple web feature, it usually sits close to the management plane and may run with elevated privileges.
This matters in cyber security because CGI code is a common place for input-handling bugs, including buffer overflows, command injection, and authentication flaws. An attacker who can reach the web interface may send a crafted request to hit a vulnerable CGI path, potentially causing a crash or taking control of the device. Defenders should treat CGI components as high-value attack surface: restrict access, patch firmware, and verify that management interfaces are not exposed where they do not belong.