A path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox. When 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).
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://github.com/googleapis/mcp-toolbox/pull/3218 Issue Tracking, Patch
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 9.3 · googleNVD modified 2026-10-25 21:10
Affected (CPE criteria) 1
cpe:2.3:a:google:mcp_toolbox_for_databases:*:*:*:*:*:*:*:*
References 1
- https://github.com/googleapis/mcp-toolbox/pull/3218 Issue Tracking, Patch