If a threat is expected to have a serious adverse effect, according to NIST SP...

NIST SP 800-30 Rev. 1 defines qualitative risk severity levels using consistent impact language. In its assessment scale,“Moderate”is explicitly tied to events that can be expected to have aserious adverse effecton organizational operations, organizational assets, individuals, other organizations, or the Nation.

A “serious adverse effect” is described as outcomes such as asignificant degradation in mission capabilitywhere the organization can still perform its primary functions but withsignificantly reduced effectiveness,significant damageto organizational assets,significant financial loss, orsignificant harm to individualsthat does not involve loss of life or life-threatening injuries. This phrasing is used to distinguish “Moderate” from “Low” (limited adverse effect) and from “High” (severe or catastrophic adverse effect).

This classification matters in enterprise risk because it drives prioritization and control selection. A “Moderate” rating typically triggers stronger treatment actions than “Low,” such as tighter access controls, enhanced monitoring, more frequent vulnerability remediation, stronger configuration management, and improved incident response readiness. It also helps leaders compare risks consistently across systems and business processes by anchoring severity to clear operational and harm-based criteria rather than subjective judgment.