Where exist a csv files load in a shinyapp.io free account

Hello, I have an application that works as an online calculator, there you can upload csv files and the calculator will take that information and perform certain calculations. Finally those results can be downloaded by the user.

Clarifications: At no time is this data stored in AWS or in any other server in the cloud. Neither is the idea.

What happens to that data that is uploaded to the application?

I understand that they exist temporarily, but, Is it possible that there is some risk of information leakage?

Can my data be stolen?