10 Common CMMC Mistakes That Delay Certification

After working with defense contractors across multiple industries and CMMC preparation cycles, certain patterns emerge consistently among organizations that stall, fail assessments, or miss contract deadlines.

• ✓Underscoping the CUI boundary. Organizations define their CUI environment too narrowly, leaving out email servers, cloud drives, remote access infrastructure, or devices used by staff working from home.
• ✓Treating CMMC as an IT project. CMMC requires participation from executive leadership, HR, facilities, finance, and operations — not just IT.
• ✓Starting the SSP too late. Some contractors wait until they are “ready” to write the SSP. The SSP should be the first significant deliverable.
• ✓Inflating the SPRS score. Overestimating compliance to look better on paper is fraud. It also creates cascading problems when the C3PAO assessment reveals a materially different picture.
• ✓Waiting too long to book a C3PAO. Book your assessment slot 6–9 months before you expect to be ready.
• ✓Not managing the POA&M actively. A POA&M that no one updates is a liability. Unresolved items with past-due dates signal that the remediation program is not being managed.
• ✓Overlooking personnel security. PS.L2-3.9.1 (screening) and PS.L2-3.9.2 (access termination) are consistently missed. Verify that your offboarding process terminates CUI access within 24 hours.
• ✓Using consumer cloud for CUI. Standard Microsoft 365, Gmail, or Dropbox do not meet DFARS 7012's cloud security requirements.
• ✓Inadequate training documentation. Training was delivered but not documented. Without records, the AT controls cannot be assessed as MET.
• ✓Letting the SSP go stale. A cloud migration, new employee, or new system in the CUI boundary not reflected in the SSP creates an instant inconsistency finding.