CVE-2026-53509
MediumCVSS 5.7Exploitation Probability (EPSS)
Low risk12th percentile - higher than 12% of all known CVEs
Summary
CKAN MCP Server before version 0.4.106 has an SSRF vulnerability that allows bypassing the IP address filter using hostname aliases such as ip6-localhost, which are not equal to localhost and are not dotted IPv4 or bracketed IPv6 literals. A remote caller can force the server to connect to local or private addresses.
Risk Assessment
An attacker can use the server to scan the internal network or obtain data from CKAN-shaped responses, potentially leading to disclosure of sensitive information.
Recommendation
Update CKAN MCP Server to version 0.4.106 or later, which includes a blocked-hostname set covering ip6-localhost and ip6-loopback.
Other vulnerabilities in CKAN MCP Server
See all- CVE-2026-73846Medium
CKAN MCP Server before 0.4.112 contains a vulnerability in canonicalizeParams in src/utils/cache.ts that serializes request parameters with unescaped ampersand, equals-sign, and vertical-bar delimiters, allowing different logical parameter sets used by buildCacheKey to collide. An attacker can prime a shared cache with a response for a victim's distinct query.
- CVE-2026-73845Medium
CKAN MCP Server before 0.4.112 contains a vulnerability in the ckan_get_mqa_quality and ckan_get_mqa_quality_details tools in src/tools/quality.ts. The isValidMqaServer function validates the server_url parameter with a prefix-only regular expression for dati.gov.it, allowing suffix-host and URL-userinfo values to target an attacker-controlled host and return a spoofed response.
- CVE-2026-73844Low
CKAN MCP Server is a tool for querying CKAN open data portals. Prior to 0.4.112, error paths reflect raw upstream response bodies and internal exception messages back to the caller instead of a sanitized, generic message. When the server is pointed at (or redirected/SSRF'd to) a host that returns a non-CKAN response, or when an internal exception occurs, the caller receives verbatim upstream content and internal detail (hostnames, internal IPs, DB errors, stack fragments). This vulnerability is fixed in 0.4.112.
Original NVD description (English source)
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`.