{"id":"CVE-2026-44430","revision":"fd3f405ad9284b37a8003662a50d0eb1","records":[{"revision":"fd3f405ad9284b37a8003662a50d0eb1","observedAt":"2026-10-27T11:12:09.678+00:00","statement":{"source":"nvd","id":"CVE-2026-44430","aliases":[],"title":"The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.7, the Registry's HTTP-based namespace verification (POST /v0/auth/http, POST /v0.1/auth/http) uses safeDialContext (internal/…","description":"The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.7, 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 blocklist (isBlockedIP, lines 125-133) relies entirely on Go stdlib's IsLoopback / IsPrivate / IsLinkLocalUnicast / IsMulticast / IsUnspecified plus a manual CGNAT range. None of these cover IPv6 6to4 (2002::/16), NAT64 (64:ff9b::/96 and 64:ff9b:1::/48 per RFC 8215), or deprecated site-local (fec0::/10) — all of which encode arbitrary IPv4 in the address bits and tunnel to RFC1918 / cloud-metadata services on dual-stack / NAT64-enabled hosts. This vulnerability is fixed in 1.7.7.","state":0,"publishedAt":"2026-05-14T21:16:46.827+00:00","modifiedAt":"2026-10-26T14:10:00.13+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":6.3,"severity":"MEDIUM"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N","score":4,"severity":"MEDIUM"}],"references":["https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-r48c-v28r-pf6v"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-44430","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Modified","weaknesses":["CWE-918"],"productCriteria":["cpe:2.3:a:lfprojects:mcp_registry:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-05-14T21:16:46.827","lastModified":"2026-10-26T14:10:00.130"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-44430","identifiers":["CVE-2026-44430"]},"retained":false,"historicalAffected":[]}],"coverage":[]}