Security

• Fixed an issue in spire-agent where the WorkloadAPI.ValidateJWTSVID endpoint did not enforce the presence of the exp (expiration) claim in JWT-SVIDs, as required by the SPIFFE specification.
  This vulnerability has limited impact: by default, SPIRE does not issue JWT-SVIDs without an expiration claim. Exploitation would require federating with a misconfigured or non-compliant trust domain.
  Thanks to Edoardo Geraci for reporting this issue.