A Firecracker MicroVM is a lightweight virtual machine built to isolate workloads with a very small attack surface. It provides stronger separation than a normal process or container, but it is still designed for speed and density, so it keeps only the virtualization features needed for cloud workloads.
In cyber security, Firecracker matters because it is used to reduce blast radius when running untrusted or semi-trusted code, including AI agents and serverless-style tasks. A microVM can help keep one session from directly reaching another, but it does not automatically protect secrets inside the workload. If the runtime can access metadata services, temporary credentials, or powerful IAM roles, an attacker who controls the application logic may still abuse that access. Defenders use Firecracker as one layer in a larger design that also needs least-privilege permissions, metadata hardening, and tight session isolation.