I found a trove of Computer Science Masters thesis unprotected on a respected uni's website I was looking for some technical documentation in relation to development of a specific piece of software, using a Google search such as "ACMESoft" "ACME_Rhino" filetype:pdf.

I found a PDF hosted on a European University's website which looked to be of interest; detailing some generic processes in relation to my search query.

I haven't read much of the PDF though, since I then went to see what other resources were available, so I browsed to a URL such as https://fileserver.someuni.ac.at/files/cs/pdf/ instead of https://fileserver.someuni.ac.at/files/cs/pdf/0815.pdf - and a full Apache webserver directory listing was presented to me.

It occurred to me that these PDFs were all people's thesis. I clicked a couple to check, and some were lengthy documents - Masters etc.

I didn't go to university, so I don't know whether these documents are supposed to be public-domain or not; but it would appear to me they shouldn't be.

Is there anything I should do in this situation?
If you feel it's incorrect for them to share the links in public, you could contact the webmaster and question their process. They possibly should disable the file listing at the directory.

Nevertheless, it's possible that for some universities access to theses is provided free of charge for other researchers to access, and you probably found the location where all of them are stored.

I don't think access should be disabled to the files individually, but indeed it is my opinion that the file directory listing should be private. They probably have a website with descriptions somewhere else, that link to the files.