CVE-2026-121139 Details

The Rapid7 Metasploit msf-ws suffers from a missing authentication vulnerability whereby the REST API grants an unauthenticated "bootstrap" exemption so that the very first administrator can be created when the users table is empty. While the table is empty, POST /api/v1/users is exempt from authentication by design: the route handler calls warden.authenticate!(scope: :admin_api), which resolves to AdminApiToken. The inherited ApiToken#authenticate! short-circuits and returns success!() whenever msf.auth_initialized is false, without ever evaluating AdminApiToken's administrator check. In that state the endpoint creates a user — including an administrator — for an entirely unauthenticated caller. This issue has been fixed in version 6.5.9.