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CVE-2026-53708 medium CVSS 6.6

Vulnerability in mcp-contextforge-gateway (CVE-2026-53708)

Summary

Vulnerability in mcp-contextforge-gateway (CVE-2026-53708). Confidential information can be exposed externally. Exploitable via httpx. Mitigation: upgrade to 1.0.3 or later.

Original description

The description as published by the source.

Summary

The /admin/gateways/test endpoint validates submitted URLs by resolving the hostname at validation time and blocking private address ranges. The HTTP client independently re-resolves DNS at connection time with no IP binding between the two operations, creating a TOCTOU window exploitable via DNS rebinding. The source code explicitly acknowledges this limitation in two separate locations.

Details

validate_gateway_test_url() in mcpgateway/common/validators.py (lines 1527–1710) calls socket.getaddrinfo() on the submitted hostname, checks whether the resolved IP falls in private, loopback, link-local, or cloud-metadata ranges (including 169.254.169.254, 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16), and accepts the URL if the result is clean. The validated URL is then passed to the HTTP client as the original hostname string, not as the validated IP address.

The HTTP client (httpx, via ResilientHttpClient) performs its own independent DNS resolution at connection time. No mechanism bridges the two resolutions:

  • The validated IP address is never passed to the HTTP client.
  • Only the original hostname is forwarded, triggering a second independent lookup.
  • No TTL enforcement, mandatory DNS-cache reuse, or IP-level socket binding is
    implemented.

The configuration options ssrf_blocked_networks (default: enabled, covers 169.254.169.254/32, link-local ranges, etc.) and ssrf_dns_fail_closed (default: True) apply exclusively at **v…

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-2026-53708 has been found in mcp-contextforge-gateway.
Attackers can target a specific entry point like httpx over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.6/10.
What to do: upgrade mcp-contextforge-gateway to 1.0.3 or later.
If unsure, ask your IT team or search "mcp-contextforge-gateway CVE-2026-53708" on the vendor's site.

CVE-2026-53708 (mcp-contextforge-gateway) — CWE-350 / CVSS v3 6.6
Attack vector: remote (network-reachable) / no user interaction
Attack surface: httpx / ResilientHttpClient / ssrf_blocked_networks / ssrf_dns_fail_closed
Patched: 1.0.3 — 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.

❓ What is the problem

A vulnerability (CWE-350) exists in mcp-contextforge-gateway. Attackers reach the vulnerable code path via httpx.

📍 Affected scope

Check the vendor advisory for the affected versions of mcp-contextforge-gateway. Attack surface: httpx / ResilientHttpClient / ssrf_blocked_networks / ssrf_dns_fail_closed.

🔥 Severity

Severity: Medium (CVSS 6.6/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 1.0.3.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'mcp-contextforge-gateway' . 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

  1. 1
    Identify exposure identify 
    grep -r 'mcp-contextforge-gateway' . | 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 mcp-contextforge-gateway を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade mcp-contextforge-gateway to 1.0.3

    ステージング環境で 1.0.3 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を含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

pip mcp-contextforge-gateway
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.3"}]}]
PyPI mcp-contextforge-gateway
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.3"}]}]

References

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