XPS foam is closed-cell extruded polystyrene foam. It is lightweight, rigid, and commonly used for insulation and packaging. In practice, that means it often appears around buildings, server rooms, electronics shipments, and industrial equipment where cushioning or thermal control is needed.
In cyber security, XPS foam matters because physical materials can affect the security of digital systems. Foam packaging can hide tampering with hardware in transit, while insulation materials can change fire risk inside facilities that house network gear or storage systems. Defenders look at these details during supply-chain checks, asset inspection, and facility hardening. The term is also useful in threat modeling: anything that protects equipment can also become a place where a malicious device, altered part, or concealment attempt might go unnoticed.