{"id":"CVE-2026-53509","published":"2026-08-21T21:21:20Z","modified":"2026-08-21T21:42:22Z","title":"@aborruso/ckan-mcp-server: SSRF via base_url allows access to internal networks (Potential fix bypass of CVE-2026-33060)","vendor":"ondata","product":"ckan-mcp-server","tier":"tail","description":{"text":"CKAN MCP Server is a tool for querying CKAN open data portals. A known vulnerability CVE-2026-33060 indicated tools including ckan_package_search and sparql_query that accept a base_url parameter had the risk of making HTTP requests to arbitrary endpoints without restriction. A fix was applied to filter out ip addresses. However, a method to bypass exists prior to version 0.4.106. CKAN MCP Server validates caller-supplied CKAN server URLs by inspecting only the parsed hostname string before issuing outbound HTTP requests. In `src/utils/http.ts`, hostname aliases such as `ip6-localhost` are not equal to `localhost`, are not dotted IPv4 literals, and are not bracketed IPv6 literals, so they pass the SSRF filter but can resolve to loopback when the server performs the request. A remote MCP caller that can invoke CKAN tools with a `server_url` can therefore make the server connect to local or private addresses and, for CKAN-shaped responses, receive response-derived data. The updated fix in version 0.4.106 replaced the single `hostname === 'localhost'` check with a blocked-hostname `Set` covering `ip6-localhost` and `ip6-loopback`.","provenance":"source","from":"CVE.org"},"cvss":{"score":5.7,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.00384,"percentile":0.32323,"provenance":"source"},"cwes":[{"id":"CWE-918","name":"Server-Side Request Forgery"}],"references":[{"url":"https://github.com/ondata/ckan-mcp-server/security/advisories/GHSA-g84h-j7jj-x32p","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/advisories/GHSA-3xm7-qw7j-qc8v","tags":["x_refsource_MISC"]},{"url":"https://github.com/ondata/ckan-mcp-server/releases/tag/v0.4.106","tags":["x_refsource_MISC"]}],"priority":{"score":10.5,"factors":[{"name":"EPSS percentile","points":6.46},{"name":"CVSS severity","points":3.99}]},"vendorSlug":"ondata","affectedVersions":[{"vendor":"ondata","product":"ckan-mcp-server","versions":["< 0.4.106"]}],"affected":[{"ecosystem":"npm","package":"@aborruso/ckan-mcp-server","vulnerableRanges":["<0.4.106"],"patched":["0.4.106"],"from":["GHSA-g84h-j7jj-x32p"],"provenance":"source"}],"euvd":{"id":"EUVD-2026-64173","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-ondata-ckan-mcp-server-cve-2026-33060","parents":[{"from":"CVE-2026-33060","to":"CVE-2026-53509","relation":"successor","confidence":"high","kind":"lineage","evidence":[{"kind":"osv-related","provenance":"source","id":"GHSA-3xm7-qw7j-qc8v","via":"related"},{"kind":"osv-related","provenance":"source","id":"GHSA-g84h-j7jj-x32p","via":"reference","url":"https://github.com/advisories/GHSA-3xm7-qw7j-qc8v"},{"kind":"version-step","provenance":"source","package":"npm:@aborruso/ckan-mcp-server","fromFixed":"0.4.85","toFixed":"0.4.106","daysApart":154}]}],"children":[{"from":"CVE-2026-53509","to":"CVE-2026-61612","relation":"incomplete-fix","confidence":"high","kind":"lineage","evidence":[{"kind":"text","provenance":"source","relation":"incomplete-fix","quote":"Prior to version 0.4.108, the SSRF guard `validateServerUrl` (added for CVE-2026-33060, extended for CVE-2026-53509) validates only the hostname string and never resolves DNS.","from":"CVE.org","in":"CVE-2026-61612"},{"kind":"osv-related","provenance":"source","id":"GHSA-g84h-j7jj-x32p","via":"related"},{"kind":"osv-related","provenance":"source","id":"GHSA-798p-78g2-v556","via":"reference","url":"https://github.com/advisories/GHSA-g84h-j7jj-x32p"},{"kind":"version-step","provenance":"source","package":"npm:@aborruso/ckan-mcp-server","fromFixed":"0.4.106","toFixed":"0.4.108","daysApart":31}]}],"packageHistory":[{"cve":"CVE-2026-33060","published":"2026-03-20","fixed":"0.4.85","kev":false},{"cve":"CVE-2026-53509","published":"2026-08-21","fixed":"0.4.106","kev":false},{"cve":"CVE-2026-61612","published":"2026-09-21","fixed":"0.4.108","kev":false},{"cve":"CVE-2026-73844","published":"2026-08-14","fixed":"0.4.112","kev":false},{"cve":"CVE-2026-73845","published":"2026-08-14","fixed":"0.4.112","kev":false}],"package":"npm:@aborruso/ckan-mcp-server"}}