# CVSS Guru

> CVSS Guru (https://cvss.guru) is a free web toolkit for the Common Vulnerability Scoring System (CVSS):
> a calculator for CVSS v4.0, v3.1, v3.0 and v2.0, a converter between versions, an AI scorer that
> suggests a CVSS v3.1 vector from a plain-language vulnerability description, a CVE lookup backed by
> the NVD, a complete CVSS guide and a REST API. No account is needed for the web tools.

Scores follow the FIRST CVSS specifications. Severity bands (v3.x/v4.0): None 0.0, Low 0.1–3.9,
Medium 4.0–6.9, High 7.0–8.9, Critical 9.0–10.0. CVSS v2.0 has no Critical band.

## Tools

- [CVSS Calculator](https://cvss.guru/): Free CVSS calculator for CVSS v4.0, v3.1, v3.0 and v2.0. Score vulnerabilities metric by metric, get the vector string, convert between versions and share results.
- [AI Scorer](https://cvss.guru/ai-scorer): Describe a vulnerability in plain English and get a suggested CVSS v3.1 base vector with a justification for every metric, benchmarked against NVD scores.
- [CVE Search](https://cvss.guru/cve-search): Look up any CVE ID and see its official CVSS v4.0, v3.1, v3.0 and v2.0 scores and vectors from the NVD, then open them in the calculator or converter.

## Documentation

- [CVSS Guide](https://cvss.guru/documentation): Complete guide to CVSS: what every metric means in v2.0, v3.0, v3.1 and v4.0, how scores and severities are calculated, and worked examples with real CVEs. Full text: https://cvss.guru/llms-full.txt
- [API Reference](https://cvss.guru/api-reference): REST API to calculate CVSS v2.0, v3.0, v3.1 and v4.0 scores, parse vector strings, convert between versions and look up CVE scores. JSON in, JSON out.

## Linking to results

- Calculator with a vector pre-filled: https://cvss.guru/?calc=v31&vector=CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  (calc = v2, v3, v31 or v4)
- Converter pre-filled: https://cvss.guru/?tool=converter&from=3.1&vector=CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

## Optional

- [Source code](https://github.com/CyberTuz/CVSS_GURU): open source (MIT)