CVE-2026-11720

Name of the Vulnerable Software and Affected Versions googleapis/mcp-toolbox (affected versions not specified)

Description A path traversal issue exists in the HTTP tool URL builder. When constructing downstream API requests, the tool substitutes user-controlled pathParams into the configured tool path and parses the result as a relative URL. Although the system verifies that the input does not modify the scheme, host, or user information, it utilizes ResolveReference for final URL resolution. Since dot segments (../) are normalized during this process, an attacker can use directory traversal sequences in path parameters to escape the configured path scope. This enables a client to force the toolbox to send requests to unintended endpoints on the same target host while forwarding the configured credentials.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.