ESPHome Device Builder Dashboard: Unauthenticated dashboard access via the HA add-on ingress site bound to all interfaces
On the Home Assistant add-on, the dashboard serves a trusted ingress site that skips authentication because the supervisor authenticates the request upstream. That site was binding 0.0.0.0. The add-on runs in host network mode for mDNS, so binding all interfaces also bound the host's LAN interface, and any device on the local network could reach http://<ha-ip>:<ingress_port>/ and get the full dashboard with no credentials.