ZITADEL 3.0.0 through 3.4.15 and 4.x before 4.17.3 contains an incorrect authorization flaw in the User Service API, which verifies user.read against the caller's organization rather than the organization owning the target user. An authenticated member holding org-scoped user.read can query GET /v2/users/{userId}/authentication_methods to learn which authentication method types users in other organizations have registered.
Analyzing vulnerability vectors…