i'm going to tell you how to prevent directory browsing.
Step 1. Always backup before you make changes.
Step 2. Open your .htaccess file
* If you can't see it, login to file browser in cPanel and go to settings and enable show hidden files.
Step 3. Paste in the following:
# BEGIN Directory Browsing Block
# END Directory Browsing Block
Step 4. Save the .htaccess file.