A path traversal flaw in the builder endpoint of Google Cloud Agent Development Kit (ADK) allows an unauthenticated attacker to read any file on the system. The defect is tied to CWE‑22 and carries a CVSS score of 8.7, indicating serious risk when the vulnerability is exploited. An attacker can provide a crafted file_path query parameter and retrieve the contents of the target file.

Google Cloud’s Agent Development Kit (ADK) version 1.9.0 through 1.21.0 running on Python are affected. The flaw specifically targets the builder endpoint exposed by the ADK.

The high CVSS score reflects significant confidentiality impact. EPSS data is currently unavailable, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector is a remote unauthenticated request to the builder endpoint, which can be crafted over HTTP/HTTPS to a publicly reachable instance. If the ADK instance is world‑exposed, the flaw can be exploited without authentication or additional privileges.