Used to evaluate the criticality of the vulnerabilities found. Based on multiple criteria :

CriteriaFirst ValueSecond ValueThird ValueFourth Value
Attack VectorNetworkAdjacentLocalPhysical
Attack ComplexityLowHigh
Privileges RequiredNoneLowHigh
User InteractionNoneRequired
ScopeUnchangedChanged
ConfidentialityNoneLowHigh
IntegrityNoneLowHigh
AvailabilityNoneLowHigh
The online calculator can be found here. Many reporting tools include this calculator and offer exporting templates. Sysreptor does an excellent job at doing that.

Temporal and Environmental Score Metrics and be used to define in more details the vulnerablity evaluated. See https://www.first.org/cvss/user-guide for more info.