CVE-2026-59178
CRITICAL · 9.8Published today, no KEV listing, no public PoC, vendor patch ready but chatter is automated feeds.
What: ESPHome Device Builder Dashboard (pre-1.0.12) silently disables authentication on upgrade when operators use legacy $USERNAME/$PASSWORD environment variables instead of the new $ESPHOME_USERNAME/$ESPHOME_PASSWORD names. CVSS 9.8 CRITICAL.
Why it matters: Authentication bypass exposes dashboards to unauthenticated access without operator awareness. Published today with vendor fix available (1.0.12, container 2026.6.2). Not yet KEV-listed. No public PoC observed. Vendor has released patched version and documented mitigation (env var rename or network isolation).
Where it's seen: Same-day CVE aggregator and security news amplification on social media (no independent researcher PoCs, no mass scanning reports, standard NVD/vendor advisory distribution).
RISK: HIGH — CRITICAL CVSS, silent auth bypass on upgrade, affects home automation infrastructure.
Description
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Attack vector
- Network
- Complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High