{"id":"CVE-2026-53509","summary":"@aborruso/ckan-mcp-server: SSRF via base_url allows access to internal networks (Potential fix bypass of CVE-2026-33060)","details":"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`.","aliases":["GHSA-g84h-j7jj-x32p"],"modified":"2026-08-23T03:53:38.928609557Z","published":"2026-08-21T21:21:20.897Z","related":["GHSA-3xm7-qw7j-qc8v","GHSA-g84h-j7jj-x32p"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53509.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-918"]},"references":[{"type":"WEB","url":"https://github.com/ondata/ckan-mcp-server/releases/tag/v0.4.106"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53509.json"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-3xm7-qw7j-qc8v"},{"type":"ADVISORY","url":"https://github.com/ondata/ckan-mcp-server/security/advisories/GHSA-g84h-j7jj-x32p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53509"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ondata/ckan-mcp-server","events":[{"introduced":"0"},{"fixed":"433464712c590ef6b353fa69ecfefbeb27de8cb7"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"0.4.106"}]}}],"versions":["v0.4.105","v0.4.103","v0.4.102","v0.4.101","v0.4.100","v0.4.99","v0.4.98","v0.4.97","v0.4.96","v0.4.95","v0.4.94","v0.4.93","v0.4.92","v0.4.91","v0.4.90","v0.4.89","v0.4.88","v0.4.87","v0.4.86","v0.4.85","v0.4.84","v0.4.83","v0.4.82","v0.4.81","v0.4.80","v0.4.79","v0.4.78","v0.4.77","v0.4.76","v0.4.75","v0.4.74","v0.4.73","v0.4.72","v0.4.71","v0.4.69","v0.4.68","v0.4.67","v0.4.66","v0.4.65","v0.4.64","v0.4.63","v0.4.62","v0.4.61","v0.4.60","v0.4.59","v0.4.58","v0.4.57","v0.4.56","v0.4.55","v0.4.54","v0.4.53","v0.4.52","v0.4.51","v0.4.50","v0.4.49","v0.4.48","v0.4.47","v0.4.46","v0.4.45","v0.4.44","v0.4.43","v0.4.42","v0.4.41","v0.4.40","v0.4.39","v0.4.38","v0.4.37","v0.4.36","v0.4.35","v0.4.34","v0.4.33","v0.4.32","v0.4.31","v0.4.30","v0.4.29","v0.4.28","v0.4.27","v0.4.26","v0.4.25","v0.4.24","v0.4.23","v0.4.22","v0.4.21","v0.4.20","v0.4.19","v0.4.18","v0.4.17","v0.4.16","v0.4.15","v0.4.14","v0.4.13","v0.4.12","v0.4.11","v0.4.10","v0.4.9","v0.4.8","v0.4.7","v0.4.6","v0.4.5","v0.4.4","v0.4.3","v0.4.2","v0.4.1","v0.4.0","v0.3.2","v0.3.1","v0.3.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53509.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N"}]}