NIST 800-171 vs CMMC 2.0: What’s the Difference and Why It Matters

Understand the frameworks driving federal cybersecurity compliance

If your business supports the Department of Defense (DoD), you’ve likely come across both NIST 800-171 and CMMC 2.0. But how do these frameworks relate to each other — and what do they mean for your next contract?

This blog clears up the confusion. We’ll explain how they connect, where they differ, and why you need to understand both to stay compliant, win bids, and protect your future in federal contracting.

1. What Is NIST 800-171?

  • Published by the National Institute of Standards and Technology, NIST SP 800-171 outlines 110 cybersecurity requirements for protecting Controlled Unclassified Information (CUI).

  • It’s required under DFARS 252.204-7012 for any contractor handling CUI in non-federal systems.

  • NIST 800-171 focuses on technical and administrative safeguards including access control, auditing, incident response, and encryption.

  • While you don’t need a formal certification for NIST 800-171, you are expected to self-assess, submit a Supplier Performance Risk System (SPRS) score, and be able to prove compliance on demand

2. What Is CMMC 2.0?

The Cybersecurity Maturity Model Certification (CMMC) 2.0 is a DoD initiative that builds directly on NIST 800-171.

It adds a layer of verification, ensuring contractors aren't just saying they’re secure — but proving it.

CMMC 2.0 introduces three certification levels, depending on the sensitivity of information handled:

Level 1: Foundational

  • Covers 17 basic security practices from FAR 52.204-21

  • Focused on protecting Federal Contract Information (FCI)

  • Requires annual self-assessment

Level 2: Advanced

  • Mirrors the full 110 NIST 800-171 controls

  • Designed for organizations handling Controlled Unclassified Information (CUI)

  • Requires third-party certification for high-priority contracts

Level 3: Expert

  • Includes additional controls from NIST 800-172

  • Applies to highly sensitive or critical national security information

  • Requires a government-led assessment

3. Key Differences Between NIST 800-171 and CMMC 2.0

Here’s how the two frameworks differ — even though they’re closely related:

Purpose

  • NIST 800-171 defines what to do.

  • CMMC 2.0 verifies that you’re actually doing it.

Compliance Method

  • NIST allows self-attestation and requires you to submit an SPRS score.

  • CMMC 2.0 requires third-party certification for most Level 2 and all Level 3 contracts.

Legal Standing

  • NIST 800-171 is a current contractual requirement under DFARS.

  • CMMC 2.0 is being phased into future DoD contracts.

Documentation Expectations

  • NIST expects an SSP (System Security Plan) and a POA&M (Plan of Action & Milestones).

  • CMMC expects evidence-backed, auditable implementation of all required controls.

Consequences of Noncompliance

  • NIST noncompliance can lead to audit findings, legal exposure under the False Claims Act, and contract loss.

  • Failing a CMMC audit disqualifies you from contract eligibility altogether.

4. Why You Need to Be Ready for Both

CMMC Level 2 is based entirely on NIST 800-171. If you’re not already working toward NIST compliance, you’re behind.

Without NIST 800-171 implementation and documentation, you can’t pass a CMMC 2.0 audit — period.

More DoD contracts are requiring CMMC readiness now, even before full enforcement begins.

NIST 800-171 and CMMC 2.0 aren’t separate paths — they’re steps in the same journey. Understanding both is essential to stay compliant, protect your data, and qualify for DoD opportunities.

Get ahead now, and your business won’t just be compliant — it’ll be competitive.

Need Help Aligning with Both Frameworks?

GSec LLC helps small businesses and federal contractors implement NIST 800-171 controls and prepare for CMMC 2.0 certification with expert guidance, clear documentation, and audit-ready systems.