MCP reference servers v2.1.0 fix eight vulnerabilities: upgrade filesystem and everything to 2.0.1 and fetch to 2026.10.24
On Oct 25 (UTC) the official Model Context Protocol servers repo shipped v2.1.0, fixing eight vulnerabilities in three reference servers: symlink races, trailing quote/whitespace path bypasses and case-insensitive symlink bypasses in filesystem; cross-origin calls over HTTP/SSE in everything; and IDNA host-name and NAT64 internal-address reachability plus robots.txt not rechecked after redirects in fetch. The maintainers warn that npm users still on date versions (2025.x/2026.x) will not be offered the upgrade and must install 2.0.1 explicitly, and that the filesystem write issue is only partly fixed on Windows.
Key Takeaways
- Eight vulnerabilities fixed across three servers (release notes)
- filesystem, 4 fixes: symlink race on writes, trailing quote/whitespace bypass, case-insensitive symlink bypass, list_directory_with_sizes leaking metadata outside allowed dirs
- everything, 1 fix: HTTP/SSE transports no longer send
Access-Control-Allow-Origin: *, so web pages can no longer call tools likeget-env - fetch, 3 fixes: IDNA host-name check vs. connection mismatch, NAT64-wrapped private IPv4, robots.txt not rechecked after redirects
- Date-versioned npm installs must run
npm install @modelcontextprotocol/[email protected]explicitly; Windows is only partly fixed


