SSRF (Server-Side Request Forgery) in github.com/modelcontextprotocol/registry (CVE-2026-44430)
Summary
SSRF in github.com/modelcontextprotocol/registry (CVE-2026-44430). Risk of unauthorized operations or information disclosure. Exploitable via POST /v0/auth/http. Mitigation: upgrade to 1.7.7 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44430 has been found in github.com/modelcontextprotocol/registry.
Attackers can target a specific entry point like POST /v0/auth/http over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.0/10.
What to do: upgrade github.com/modelcontextprotocol/registry to 1.7.7 or later.
If unsure, ask your IT team or search "github.com/modelcontextprotocol/registry CVE-2026-44430" on the vendor's site.
CVE-2026-44430 (github.com/modelcontextprotocol/registry) — CWE-918 / CVSS v3 4.0
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /v0/auth/http / POST /v0.1/auth/http / safeDialContext / isBlockedIP
Patched: 1.7.7 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
SSRF (CWE-918) exists in github.com/modelcontextprotocol/registry. Attackers reach the vulnerable code path via POST /v0/auth/http without authentication.
Check the vendor advisory for the affected versions of github.com/modelcontextprotocol/registry. Attack surface: POST /v0/auth/http / POST /v0.1/auth/http / safeDialContext / isBlockedIP.
Severity: Medium (CVSS 4.0/10). Risk of unauthorized operations or information disclosure.
Update to 1.7.7.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /v0/auth/http requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/modelcontextprotocol/registry' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/modelcontextprotocol/registry' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/modelcontextprotocol/registryを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /v0/auth/http' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /v0/auth/httpへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade github.com/modelcontextprotocol/registry to 1.7.7ステージング環境で 1.7.7 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /v0/auth/http on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com