You can rate a vulnerability by using the DREAD ratings. For every vulnerability, a rating between 0 and 10 is assigned for each of the DREAD categories including Damage potential, Reproducibility, Exploitability, Affected users, and Discoverability. The cumulative DREAD rating is the sum of the individual category ratings. The higher the DREAD rating, the more serious the vulnerability. You should prioritize vulnerabilities according to their DREAD rating.
The DREAD model, shown here, is an effective tool for quantifying specific risks. For every vulnerability, a rating between 0 and 10 is assigned for each of the DREAD categories:
Damage potential
Reproducibility
Exploitability
Affected users
Discoverability
Reference
https://www.owasp.org/index.php/Threat_Risk_Modeling