The Yarbo cloud does not enforce per-device or per-user authorization. Any client possessing valid credentials, whether the shared hard-coded credentials or legitimate per-user credentials, can subscribe to wildcard topics covering all robots globally, and can publish to any robot's command topic using only the robot's serial number (disclosed in the telemetry stream). Even after removal of hard-coded credentials from the app, a single compromised credential could still provide fleet-wide access without per-device access controls.
Analyzing vulnerability vectors…