{"apiVersion":"1.0","identifier":"CVE-2026-53509","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":"2026-08-21T22:16:38","lastModifiedAt":"2026-08-21T22:16:38","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53509","cvssScore":5.7,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","epssProbability":0.00217,"riskScore":0.58,"affectedProduct":"CKAN MCP Server","affectedVersions":"<0.4.106","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-53509","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-53509","en":"https://www.redsauce.net/en/cves/CVE-2026-53509","fr":"https://www.redsauce.net/fr/cves/CVE-2026-53509","pt":"https://www.redsauce.net/pt/cves/CVE-2026-53509","de":"https://www.redsauce.net/de/cves/CVE-2026-53509","sk":"https://www.redsauce.net/sk/cves/CVE-2026-53509","el":"https://www.redsauce.net/el/cves/CVE-2026-53509"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-53509"}}