MinIO is a High Performance Object Storage released under GNU Affero General Public License v3.0. `If-Modified-Since` and `If-Unmodified-Since` headers when used with anonymous requests by sending a random object name requests can be used to determine if an object exists or not on the server on a specific bucket and also gain access to some amount of information such as `Last-Modified (of the latest version)`, `Etag (of the latest version)`, `x-amz-version-id (of the latest version)`, `Expires (metadata value of the latest version)`, `Cache-Control (metadata value of the latest version)`. This conditional check was being honored before validating if the anonymous access is indeed allowed on the metadata of an object. This issue has been addressed in commit `e0fe7cc3917`. Users must upgrade to RELEASE.2024-05-27T19-17-46Z for the fix. There are no known workarounds for this issue.