NIST 800-171 3.1.22 (AC.L2-3.1.22): Public Information

Control CUI posted or processed on publicly accessible systems.

NIST SP 800-171 Rev. 2, requirement 3.1.22

CMMC Level 2 practice AC.L2-3.1.22Published 2026-11-11

What 3.1.22 means in practice

Websites, social media and public repositories must never carry CUI. Name the people allowed to publish, review content before it goes out, check what is already public, and keep a way to pull anything that slips through.

SPRS points and the CMMC POA&M

CMMC Level 2 practice: AC.L2-3.1.22
SPRS points: 1 point. When it is not met, the DoD Assessment Methodology subtracts 1 from the score of 110.
CMMC POA&M: Never. 32 CFR 170.21(a)(2)(iii) names 3.1.22 among the 6 requirements a CMMC POA&M may never include, whatever their point value.

Sources: NIST SP 800-171 DoD Assessment Methodology, version 1.2.1 (June 24, 2020), Annex A; 32 CFR 170.21, Plan of Action and Milestones requirements.

What an assessor checks for 3.1.22

NIST SP 800-171A gives 5 determination statements for 3.1.22, each found satisfied or other than satisfied. Determine if:

3.1.22[a] individuals authorized to post or process information on publicly accessible systems are identified.
3.1.22[b] procedures to ensure CUI is not posted or processed on publicly accessible systems are identified.
3.1.22[c] a review process is in place prior to posting of any content to publicly accessible systems.
3.1.22[d] content on publicly accessible systems is reviewed to ensure that it does not include CUI.
3.1.22[e] mechanisms are in place to remove and address improper posting of CUI.

NIST SP 800-171A (June 2018), assessment objectives for 3.1.22

Evidence that shows 3.1.22 is met

A list of the people authorized to post to public systems.
The review procedure for content before publication, and records of those reviews.
Periodic reviews of public content for CUI.
The procedure for removing CUI that was posted by mistake.

How PolicyCortex gathers the evidence

No PolicyCortex collector reads the evidence for 3.1.22. Your team provides the evidence listed above.

Related pages

Calculator: SPRS score calculator: mark 3.1.22 and the other 109 requirements and see the score.
Sample package: Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.
Family: All 22 Access Control requirements (3.1).
Previous: 3.1.21: Portable Storage Use
Next: 3.2.1: Security Awareness
All requirements: All 110 NIST SP 800-171 requirements, by family.

Related records

Guides and articles describe the work. The evidence that work produces is described in three proof pages, the architecture page, and the two pages on authorization.

proof.state: Proof of State. What the environment was, as of a date someone else picks: point-in-time records, content hashed and chained.
proof.change: Proof of Change. Who or what altered the environment, under what authority, with before and after state hashes.
proof.agency: Proof of Agency. What a machine was permitted to do before it acted, what it did, and what would have stopped it.
architecture: Architecture. How the chain is built and where the evidence is stored in each delivery mode.
authorization: Continuous ATO. How an authorizing official's decision is recorded with its package, and how the authorized system is checked against it every hour.
baseline: NIST SP 800-53. The Low, Moderate and High baselines as evidence, with the SSP, SAR and POA&M generated from one record.