In large networks, security teams receive hundreds of CVE notifications every day. It is resource-intensive to patch all vulnerabilities at once and immediately. CVE Severity is based on the CVSS (Common Vulnerability Scoring System) system, which measures the risk of vulnerabilities from 0.0 to 10.0, and serves as a compass for teams to prioritize which threats to address.
Severity Levels and Response Strategies
The CVSS framework categorizes vulnerabilities into four different severity levels. Each level requires a different response time:
Critical Level (CVSS 9.0 – 10.0)
Characteristics: Can be exploited over the Internet, without user interaction, and without requiring any special privileges. Allows for full system control (Remote Code Execution).
Strategy: Urgent Incident Response. No scheduled maintenance is expected.
Response Time: Within 24 - 48 hours. If no official patch is available, immediate virtual patching is applied through the Web Application Firewall (WAF).
High (CVSS 7.0 - 8.9)
Features: Allows Privilege Escalation or bypassing of critical security filters. However, exploitation may require specific user actions, such as local network access or phishing.
Strategy: Accelerated Patching. Monthly queues are unexpectedly pushed into the next update cycle.
Response Time: Within 1 - 2 weeks.
Medium (CVSS 4.0 - 6.9)
Features: Requires complex conditions, internal user permissions, or physical access to exploit. Impact is typically limited and does not bring down the entire infrastructure.
Strategy: Scheduled Patching. Scheduled to fit into standard IT maintenance cycles and monthly routine update windows.
Response Time: Within 30 - 90 days.
Low (CVSS 0.1 - 3.9)
Characteristics: Minimal security impact. Typically small leaks such as software version number disclosure (information disclosure) and not sufficient for a single cyberattack.
Strategy: Low Priority / Monitoring Only. Performed during major system updates or when resources allow.
Response Time: When resources and time are available (no time limit).
Conclusion
Organizations are moving from a haphazard "patch everything" approach to a risk-based, systematic defense model by directly aligning their response to the severity of CVEs.
