{"id":"CVE-2026-11720","aliases":["GHSA-vwxw-jrg6-9jxv"],"title":"MCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints","summary":"MCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","vendor":"googleapis","product":"github.com/googleapis/mcp-toolbox","ecosystem":"go","affected":["github.com/googleapis/mcp-toolbox < 1.3.0"],"patched":["github.com/googleapis/mcp-toolbox 1.3.0"],"published":"2026-06-29","updated":"2026-09-04","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-vwxw-jrg6-9jxv","references":[{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-11720"},{"url":"https://github.com/googleapis/mcp-toolbox/pull/3218"},{"url":"https://github.com/googleapis/mcp-toolbox/commit/80a66021205e032a424fff87b3dc6d92da58aa77"},{"url":"https://github.com/googleapis/mcp-toolbox"},{"url":"https://github.com/googleapis/mcp-toolbox/releases/tag/v1.3.0"}],"tags":["osv","go"],"epss":0.00533,"epssPercentile":0.42611,"ingestedAt":"2026-09-05T19:33:48.345Z","slug":"CVE-2026-11720","body":"## Overview\n\nA path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox.\n\nWhen constructing downstream API requests, the URL builder substitutes user-controlled pathParams into the configured tool path and parses the resulting string as a relative URL. While it checks that the input does not alter the scheme, host, or user info, it relies on ResolveReference for the final URL resolution. Because dot segments (../) are normalized during this resolution step, an attacker can supply path parameters containing directory traversal sequences to escape the operator-configured path scope. This allows the client to coerce the toolbox into making requests to unintended endpoints on the same target host while forwarding the toolbox's configured credentials (e.g., bypassing a restricted path like /api/v1/users/{{.id}} to reach /admin/secrets).\n\n## Affected packages\n\n- `github.com/googleapis/mcp-toolbox < 1.3.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `github.com/googleapis/mcp-toolbox 1.3.0`","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}