Glossary
CVSS
A 0 to 10 score for how severe a flaw is in theory.
The Common Vulnerability Scoring System rates the technical severity of a vulnerability from 0 to 10, based on things like how it is reached and what an attacker gains. It is maintained by FIRST.
CVSS does not tell you whether a flaw is being exploited. A high score on a flaw nobody uses can outrank a lower score on one under active attack, which is why it works best together with KEV and EPSS.