# Source: https://github.com/aquasecurity/trivy/blob/main/docs/guide/supply-chain/vex/sbom-ref.md

# VEX SBOM Reference

!!! warning "EXPERIMENTAL"
    This feature might change without preserving backwards compatibility.

## Using externally referenced VEX documents

Trivy can discover and download VEX documents referenced in the `externalReferences` of a scanned CycloneDX SBOM. This
requires the references to be of type `exploitability-statement`.

To be picked up by Trivy, following top level content needs to be part of a CycloneDx SBOM to dynamically resolve a
remotely hosted file VEX file at the location `https://vex.example.com`:

```
  "externalReferences": [
    {
      "type": "exploitability-statement",
      "url": "https://vex.example.com/vex"
    }
  ]
```

This can also be used to dynamically retrieve VEX files stored on GitHub with an `externalReference` such as:

```
  "externalReferences": [
    {
      "type": "exploitability-statement",
      "url": "https://raw.githubusercontent.com/aquasecurity/trivy/refs/heads/main/.vex/trivy.openvex.json"
    }
  ]
```

This is not enabled by default at the moment, but can be used when scanning a CycloneDx SBOM and explicitly specifying
`--vex sbom-ref`.

```shell
$ trivy sbom trivy.cdx.json --vex sbom-ref
2025-01-19T13:29:31+01:00       INFO    [vex] Retrieving external VEX document from host vex.example.com type="externalReference"
2025-01-19T13:29:31+01:00       INFO    Some vulnerabilities have been ignored/suppressed. Use the "--show-suppressed" flag to display them.
```

All the referenced VEX files are retrieved via HTTP/HTTPS and used in the same way as if they were explicitly specified
via a [file reference](./file.md).