CVSS (Common Vulnerability Scoring System) is a free and open industry standard for assessing the severity of computer security vulnerabilities. It provides a numerical score from 0 to 10, with 10 being the most severe, along with a qualitative severity rating (None, Low, Medium, High, Critical).

What is the difference between CVSS v3.1 and v4.0?

CVSS v4.0 is the latest version released in 2023. It introduces new metrics like Attack Requirements, and separates impact into Vulnerable System and Subsequent System categories. It provides more granular scoring and better reflects modern attack patterns compared to v3.1.

How are CVSS severity ratings determined?

CVSS scores map to severity ratings: 0.0 is None, 0.1-3.9 is Low, 4.0-6.9 is Medium, 7.0-8.9 is High, and 9.0-10.0 is Critical. These ratings help organizations prioritize vulnerability remediation efforts.

What is a CVSS vector string?

A CVSS vector string is a compact text representation of the metric values used to calculate a score. For example, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H represents a critical vulnerability. It can be shared and imported into any CVSS calculator.

Is this CVSS calculator free to use?

Yes, this CVSS calculator is completely free to use with no signup or registration required. Your score history is saved locally in your browser. No data is sent to any server.

Free Online CVSS Score Calculator (No Signup)

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CVSS Severity Ratings

Rating	Score Range
None	0.0
Low	0.1 – 3.9
Medium	4.0 – 6.9
High	7.0 – 8.9
Critical	9.0 – 10.0

What is CVSS?

The Common Vulnerability Scoring System (CVSS) is an open framework for communicating the characteristics and severity of software vulnerabilities. It produces a numerical score (0–10) reflecting severity, and a vector string that captures the specific metrics used.

Metric Groups

Base: Intrinsic qualities of a vulnerability (always required)
Temporal: Characteristics that change over time (exploit maturity, patch availability)
Environmental: Customized scoring for your specific environment

Tips

Hover over any metric value to see a tooltip explanation
Click the explanation area under each metric for detailed guidance
Use Import to paste in a vector string from an NVD advisory
Save scores to history and compare vulnerabilities side by side

Quick Presets

CVSS Severity Ratings

What is CVSS?

Metric Groups

Tips

📋 Import Vector String

💾 Save Score to History