GO-2026-5607 MCP Registry has an unauthenticated SSRF: HTTP namespace verification dials 6to4 / NAT64 / site-local IPv6 addresses, bypassing private-address allowlist in github.com/modelcontextprotocol/registry

MCP Registry has an unauthenticated SSRF: HTTP namespace verification dials 6to4 / NAT64 / site-local IPv6 addresses, bypassing private-address allowlist in github.com/modelcontextprotocol/registry...

GHSA-R48C-V28R-PF6V MCP Registry has an unauthenticated SSRF: HTTP namespace verification dials 6to4 / NAT64 / site-local IPv6 addresses, bypassing private-address allowlist

Summary The Registry's HTTP-based namespace verification POST /v0/auth/http, POST /v0.1/auth/http uses safeDialContext internal/api/handlers/v0/auth/http.go:67-110 to refuse dialling private/internal addresses when fetching the well-known public-key file from a publisher-supplied domain. The...