Specifies the severity or risk scoring methodology or standard used.
CVSSv2 - Common Vulnerability Scoring System v2
CVSSv3 - Common Vulnerability Scoring System v3
CVSSv31 - Common Vulnerability Scoring System v3.1
CVSSv4 - Common Vulnerability Scoring System v4
any other
OWASP - OWASP Risk Rating Methodology
SSVC - Stakeholder Specific Vulnerability Categorization (all versions)
Specifies the severity or risk scoring methodology or standard used.