Forms with Asset/File Upload

Hi everyone,

I have a question, how exactly is the asset/file uploading via form/inbox working?

I’ve created a simple form (in React) with a fetch request via the /inbox/submit/token-endpoint.
Everything works and is being saved, except the file upload.
The data is transferred via FormData as body and with a multipart/form-data header.

The response I’m getting back from Cockpit is an empty attachments array.

Do I need to give the role access to upload assets?
Where are the assets/files uploaded?

Thanks in advance.