FreeScout Allows Unauthenticated Access to Legacy Attachment Files

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.221, FreeScout's attachment download route skips token authentication for any attachment whose `token_type` is set to `1` (`TOKEN_TYPE_LEGACY`). Because this route is unauthenticated and the file path is deterministic, an unauthenticated remote attacker can download any attachment that was created by an older version of FreeScout without possessing a valid token or session. Version 1.8.221 contains a fix.