4.3. Security scanning
By clicking the on the vulnerability or fixable count next to a tab you can jump into the security scanning information for that tag. There you can find which CVEs your image is susceptible to, and what remediation options you may have available.
Keep in mind that image scanning only lists vulnerabilities found by the Clair image scanner. What each user does about the vulnerabilities that are uncovered is completely up to that user. The Red Hat Quay superuser does not act on those vulnerabilities found.