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CVE-2026-61612: CVE-2026-61612: Server-Side Request Forgery Bypass via DNS Resolution in CKAN MCP Server

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CVE-2026-61612: Server-Side Request Forgery Bypass via DNS Resolution in CKAN MCP Server

Vulnerability ID: CVE-2026-61612
CVSS Score: 5.7
Published: 2026-09-22

An input validation bypass in the CKAN MCP Server (NPM package @aborruso/ckan-mcp-server) prior to version 0.4.108 allows remote attackers to perform Server-Side Request Forgery (SSRF). The application's server URL validation mechanism checked hostnames only as literal strings without performing pre-connection DNS resolution. An attacker can bypass these checks using hostnames that resolve to loopback, private, or link-local IP addresses, including the AWS Instance Metadata Service (IMDS). This is the third documented bypass of this protection mechanism, succeeding previous incomplete mitigations in CVE-2026-33060 and CVE-2026-53509.

TL;DR

A Server-Side Request Forgery (SSRF) vulnerability in @aborruso/ckan-mcp-server before v0.4.108 allows low-privilege remote attackers to query local or internal network endpoints, including AWS IMDS, by passing domains that resolve to restricted IPs, bypassing the string-only validation checks.

⚠️ Exploit Status: POC

Technical Details

  • CWE ID: CWE-918
  • Attack Vector: Network (AV:N)
  • CVSS Severity Score: 5.7 (Medium)
  • EPSS Score: 0.00221 (Percentile: 12.95%)
  • Exploit Status: poc
  • KEV Status: Not Listed

Affected Systems

  • Node.js applications running @aborruso/ckan-mcp-server version < 0.4.108

Mitigation Strategies

  • Upgrade @aborruso/ckan-mcp-server to version 0.4.108 or higher to enforce DNS-resolved IP checks.
  • Implement outbound network firewall constraints (egress filtering) to block requests to loopback addresses, private networks, and cloud metadata targets.
  • Enable the domain validation allowlist feature using the CKAN_ALLOWED_DOMAINS environment variable to restrict outbound connections to approved targets.

Remediation Steps:

  1. Run 'npm install @aborruso/ckan-mcp-server@latest' to update the package to v0.4.108 or higher.
  2. Configure environment configuration using 'export CKAN_ALLOWED_DOMAINS="data.gov,open.canada.ca,dati.gov.it"' to limit target access.
  3. Configure cloud security group or local iptables firewall policies to deny traffic from the MCP server container to 169.254.169.254 and 127.0.0.1.

References

Read the full report for CVE-2026-61612 on our website for more details including interactive diagrams and full exploit analysis.

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