What Qualifies as a Significant Change Requiring CMMC Reassessment?

Understanding Significant Changes

Not every change to your IT environment triggers a CMMC reassessment. The key question is whether the change materially impacts your security posture or assessment scope.

Examples of Significant Changes

• Network architecture overhaul — new segmentation, topology changes
• Cloud migration — moving CUI to a new cloud environment
• New CUI data flows — CUI processed on previously out-of-scope systems
• Security tool replacement — changing your SIEM, endpoint protection, or MFA solution
• Facility changes — new physical locations processing CUI
• Mergers/acquisitions — integrating new IT environments

Examples of Non-Significant Changes

• Routine patching and updates
• Employee onboarding/offboarding (normal turnover)
• Hardware refresh with equivalent systems
• Minor policy updates

Best Practice

Before making any major change, consult with your Affirming Official and perform a security impact analysis (CM.L2-3.4.4). Document your assessment of whether the change is significant. When in doubt, err on the side of treating it as significant — the consequences of non-compliance are much greater than the cost of reassessment.