I can see the files and folders (no blank index.php). Is this a security issue?

Hello. I'm adding a URL to site details here... It's one that would be common on all EasySocial installs... If I visit it, I can get a listing of files and folders... Is this anything to worry about? I notice the same for some, but not all, of it's sub-folders too?

I'm not an expert but I thought a blank index.php / index.html should go in folders to protect them from unwelcome eyes?

Thanks