The stack effect is natural airflow caused by temperature differences: warm air becomes less dense, rises, and is replaced by cooler air moving in below. In enclosures, racks, and fanless devices, this can create a predictable vertical path for heat to leave the system.
In cyber security, stack effect matters because temperature affects reliability. Routers, cameras, kiosks, and servers can throttle, reboot, or fail if hot air is trapped around processors, power supplies, or storage. Attackers may try to worsen cooling by blocking vents, placing devices in poor airflow conditions, or forcing sustained high load until thermal protections trigger. Defenders use the same principle by designing chassis and rack layouts that guide exhaust upward, separating intake and exhaust paths, and monitoring temperature so overheated equipment is noticed before it becomes a denial-of-service problem.