{"id":"CVE-2026-53509","state":"PUBLISHED","title":"@aborruso/ckan-mcp-server: SSRF via base_url allows access to internal networks (Potential fix bypass of CVE-2026-33060)","description":"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`.","publishedAt":"2026-08-21T21:21:20.897Z","updatedAt":"2026-08-21T21:42:22.500Z","severity":{"score":5.7,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["ondata ckan-mcp-server"],"affected":[{"vendor":"ondata","product":"ckan-mcp-server","versions":[{"version":"< 0.4.106","status":"affected"}]}],"references":["https://github.com/ondata/ckan-mcp-server/security/advisories/GHSA-g84h-j7jj-x32p","https://github.com/advisories/GHSA-3xm7-qw7j-qc8v","https://github.com/ondata/ckan-mcp-server/releases/tag/v0.4.106"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53509.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53509","state":"PUBLISHED","datePublished":"2026-08-21T21:21:20.897Z","dateUpdated":"2026-08-21T21:42:22.500Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-09T17:05:25.060Z"},"containers":{"cna":{"title":"@aborruso/ckan-mcp-server: SSRF via base_url allows access to internal networks (Potential fix bypass of CVE-2026-33060)","descriptions":[{"lang":"en","value":"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`."}],"affected":[{"vendor":"ondata","product":"ckan-mcp-server","versions":[{"version":"< 0.4.106","status":"affected"}]}],"references":[{"url":"https://github.com/ondata/ckan-mcp-server/security/advisories/GHSA-g84h-j7jj-x32p","name":"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","name":"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","name":"https://github.com/ondata/ckan-mcp-server/releases/tag/v0.4.106","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.7,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-21T21:21:20.897Z"},"source":{"advisory":"GHSA-g84h-j7jj-x32p","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T21:35:04.552283Z","id":"CVE-2026-53509","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-21T21:42:22.500Z"}}]}}}