Vulnerability · Published Jun 29, 2026 · Assigned by Google
CVE-2026-11720Path Traversal in googleapis/mcp-toolbox HTTP Tool URL Builder
Critical 9.3
In plain English
A critical-severity path traversal in MCP Toolbox for Databases (googleapis/mcp-toolbox) from Google. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/googleapis/mcp-toolbox | 1.3.0 | GHSA-vwxw-jrg6-9jxv |
| Go | github.com/googleapis/mcp-toolbox | 1.3.0 | GO-2026-6411 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MCP Toolbox for Databases (googleapis/mcp-toolbox) | 0 – before 1.3.0 |
Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N