Is a CUI enclave a legitimate way to cut CMMC scope?

A CUI enclave functions by creating a clearly defined, isolated environment for all CUI and the associated assets. This isolation can be achieved through a combination of physical and logical segmentation, such as dedicated networks, virtual machines, or specific cloud environments. The primary benefit is that only the systems within this enclave, and those directly supporting its security and operation, fall within the CMMC assessment boundary. This significantly reduces the number of systems, applications, and personnel that must meet CMMC requirements, leading to potentially lower implementation costs and assessment complexity compared to an enterprise-wide approach.

Practitioners often err by underestimating the pervasive nature of CUI or failing to adequately segment all relevant assets. A common pitfall is incomplete CUI identification, where some CUI remains outside the enclave, or where systems outside the enclave still interact with CUI without appropriate controls. Effective implementation requires a comprehensive CUI inventory, detailed data flow mapping, and robust network architecture to prevent CUI 'spillover' or unauthorised access. Furthermore, the enclave itself must fully meet all CMMC Level 2 requirements; merely isolating CUI does not inherently make the enclave compliant without the necessary security practices and controls.