GHSA-fphv-w9fq-2525

# Security Disclosure: Improper validation of configured threshold for delegations

## Summary

A compromised or misconfigured TUF repository can have the configured value of signature thresholds set to 0, which effectively disables signature verification.

## Impact

Unathorized modification to TUF metadata files is possible at rest, or during transit as no integrity checks are made.

## Patches

Upgrade to v2.3.1

## Workarounds

Always make sure that the TUF metadata roles are configured with a threshold of at least 1.

## Affected code:

The `metadata.VerifyDelegate` did not verify the configured threshold prior to comparison. This means that a misconfigured TUF repository could disable the signature verification by setting the threshold to 0, or a negative value (and so always make the signature threshold computation to pass).