CKAN MCP Server SSRF via DNS-name resolution bypass

The @aborruso/ckan-mcp-server SSRF guard fails to resolve DNS names, allowing attackers to bypass validation and reach internal addresses (127.0.0.1, 169.254.169.254, RFC-1918) through hostname arguments. This is the third bypass of the same validation function, affecting all versions through 0.4.107.

Disclosed 22 September 2026 · Record updated 1 October 2026

Impact

Remote unauthenticated clients can reach internal hosts and cloud metadata (IMDS) on self-hosted HTTP deployments; official Cloudflare Worker endpoint is unaffected due to sandboxing.

Our coverage

A fortress wall with three identical breach points stands exposed as guards repeatedly fail to verify the true identity of approaching messengers before granting passage to forbidden inner chambers.

Vulnerabilities

CKAN MCP server SSRF guard bypassed for the third time

An advisory published on 22 September 2026 says the CKAN MCP server's URL check never resolves DNS, letting callers reach loopback and cloud metadata endpoints.

22 Sept 2026

Sources

github.comhttps://github.com/advisories/GHSA-798p-78g2-v556