An arXiv study submitted on 21 May identified 7,973 live remote MCP servers and found that 40.55% expose tools without authentication; it also tested 119 OAuth-enabled servers and obtained 9 CVE IDs.
Tip: inventory every remote MCP server your agents connect to and check whether it authenticates before you ask whether it authenticates well. If the answer to “what servers do we use?” is a shrug, that’s finding number one.
Sources: arXiv
