CVE-2026-591789.8CriticalCWE-306

CVE-2026-59178: ESPHome Device Builder: Renamed auth env vars silently disable dashboard authentication on upgrade

esphome · device-builder

Affected: esphome device-builder · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.8%probability of exploitation in the next 30 days

56th percentile

050100

Higher than 56% of scored CVEs

9.8CriticalCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

esphome · device-builder< 1.0.12

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Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Missing Authentication · Authentication
Vendor: esphome
Published: September 2026
Band: Unlikely (under 1%), September 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-59178 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.