CVE-2026-59178
moderateSilent auth loss in ESPHome Device Builder dashboard after env var rename
ESPHome Device Builder renamed its dashboard authentication environment variables from USERNAME/PASSWORD to ESPHOME_USERNAME/ESPHOME_PASSWORD with no backward-compatible fallback, so standalone deployments that set only the bare names silently lose authentication after upgrading. Because using_password resolves to false, both the REST auth middleware and the WebSocket login gate are disabled, leaving the dashboard open to any unauthenticated client with network access to its port; the only warning is a startup log banner that detached containers (docker run -d) never surface. An attacker who reaches the port gains full dashboard control — editing device configurations, flashing firmware, and per ESPHome's threat model, running arbitrary code at compile time and reading/writing files in the config and data directories. Only standalone Docker/pip deployments relying on the bare env vars are affected; Home Assistant add-on installs (which use --ha-addon and supervisor ingress) and deployments using --username/--password flags or the new ESPHOM_E* names are not. No public proof of concept is known and the flaw is not in the CISA KEV catalog.
What to do: Check whether your deployment still sets only USERNAME/PASSWORD and whether startup logs show the 'WITHOUT AUTHENTICATION' banner (inspect with 'docker logs' on detached containers). Migrate credentials to the ESPHOM_EUSERNAME/ESPHOME_PASSWORD environment variables or the --username/--password CLI flags, and immediately restrict network access to the dashboard port (bind to localhost or place behind a firewall/VPN) since an exposed dashboard grants host-equivalent code execution. Home Assistant add-on installations need no action.
| ESPHome (esphome) esphome-device-builder (ESPHome Device Builder dashboard, pip package) | 2026.6.0 and later post-rename releases, when configured via the legacy USERNAME/PASSWORD environment variables |
| ESPHome (esphome) ghcr.io/esphome/esphome container, 'dashboard' subcommand without --ha-addon | Images shipping the post-rename device-builder (from 2026.6.0 onward) that inherited only bare USERNAME/PASSWORD env vars |
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
ESPHome Device Builder Dashboard is a dashboard for the ESPHome home management software. Prior to version 1.0.12, the dashboard reads its authentication credentials from `$ESPHOME_USERNAME` and `$ESPHOME_PASSWORD`. Earlier versions, and the legacy `esphome` dashboard, read the bare `$USERNAME` and `$PASSWORD` instead. When the env vars were renamed the bare names were dropped with no fallback, so an operator who had protected their dashboard with `USERNAME` / `PASSWORD` (as the older getting started guide documented) loses authentication on upgrade and the dashboard starts open to anyone who can reach its port. The issue is fixed in 1.0.12. The bare `$USERNAME` / `$PASSWORD` are accepted again as a deprecated fallback so previously protected instances stay protected across the upgrade without operator intervention, with a loud deprecation warning at startup directing operators to rename them to `$ESPHOME_USERNAME` / `$ESPHOME_PASSWORD`. The fallback is gated on `$PASSWORD` being set and is only adopted as a pair, so the OS provided `$USERNAME` is never read on its own and the original collision footgun stays closed. A lone bare `$PASSWORD` with no username still fails loud as a credential mismatch rather than starting unauthenticated. This restores compatibility rather than failing closed on the legacy names, because the priority is that an instance which was protected before the upgrade stays protected without the operator having to act; the deprecation warning plus a future removal handles the migration. Operators should migrate to the `$ESPHOME_*` names. The esphome container delivers the fix in the 2026.6.2 release, which bumps its pinned `esphome-device-builder` version to 1.0.12. Without upgrading, restore authentication immediately by setting the new env vars to the same values, on any affected version. Alternatively, do not expose the dashboard port to untrusted networks, and check the startup logs for the `WITHOUT AUTHENTICATION` banner to confirm whether a given instance is currently open.
- Ecosystems
- pip
- Weakness
- CWE-306
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- GHSA
- GHSA-rrxg-g2pf-6hh4 (critical)
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