GHSA-m983-7426-5hrj Ech0 authenticated user-list exposed data via public `/api/allusers` endpoint

• Go github.com/lin-snow/ech0: < 1.4.8-0.20260322121226-acbf1fd71011 → fixed in 1.4.8-0.20260322121226-acbf1fd71011

Summary A public access-control flaw allows unauthenticated users to retrieve the full user list from `GET /api/allusers`. This exposes user profile metadata to anyone who can reach the application and enables remote user enumeration. Details The vulnerable route is registered as a public endpoint: • `internal/router/user.go:17` • `appRouterGroup.PublicRouterGroup.GET("/allusers", h.UserHandler.GetAllUsers())` However, the handler appears to have been intended as an authenticated endpoint: • `internal/handler/user/user.go:177-185` • API annotations indicate an authentication requirement via `@Security ApiKeyAuth` This creates a mismatch between the documented security model and the actual routing configuration. As a result, requests to `GET /api/allusers` succeed without authentication and return user records, including profile metadata such as usernames, email addresses, role-related flags, avatar values, and locale information. A negative control against another endpoint that correctly requires authentication further supports that this exposure is unintended: `GET /api/user` returns `401 Unauthorized` when no token is supplied, while `GET /api/allusers` remains publicly accessible. Impact • Type: Access control bypass / unauthenticated data exposure • Who is impacted: Any deployment exposing the API to untrusted networks, and all users whose profile metadata is returned by the endpoint • Security impact: Enables remote user enumeration and disclosure of user profile metadata, which may facilitate account reconnaissance, phishing, and targeted credential attacks • Attack preconditions: None beyond network access to the affected API endpoint