CVE-2026-59178
Received Received - Intake

ESPHome Device Builder Dashboard Authentication Bypass

Publication date: 2026-09-14

Last updated on: 2026-09-14

Assigner: GitHub, Inc.

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.

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Meta Information

Published
2026-09-14
Last Modified
2026-09-14
Generated
2026-09-14
AI Q&A
2026-09-14
EPSS Evaluated
N/A
NVD
CVE-2026-59178
EUVD
EUVD-2026-77758

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
esphome esphome_device_builder to 1.0.12 (exc)
esphome esphome From 2026.6.2 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-306 The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

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Executive Summary

This vulnerability affects ESPHome Device Builder Dashboard versions before 1.0.12. It involves a change in how authentication credentials are read from environment variables. Older versions used $USERNAME and $PASSWORD, while newer versions switched to $ESPHOME_USERNAME and $ESPHOME_PASSWORD. The issue is that the bare $USERNAME and $PASSWORD were removed without a fallback, causing previously protected dashboards to become open to anyone if those variables were set. Version 1.0.12 restores compatibility by accepting the old variables as a deprecated fallback with a warning.

Detection Guidance

Check if the ESPHome Device Builder Dashboard is running without authentication by inspecting startup logs for the 'WITHOUT AUTHENTICATION' banner. Verify environment variables set for authentication credentials. Ensure $ESPHOME_USERNAME and $ESPHOME_PASSWORD are configured instead of legacy $USERNAME and $PASSWORD.

Impact Analysis

If you upgraded from an older version to a version before 1.0.12 and had authentication set up using $USERNAME and $PASSWORD, your dashboard could become accessible without any authentication. This means anyone who can reach the dashboard port could gain full access, potentially allowing them to control connected devices or view sensitive information. The impact is high as it affects confidentiality, integrity, and availability of the system.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, which may violate compliance requirements under GDPR, HIPAA, or other regulations. Unauthorized access risks exposing personal or health information, leading to potential legal penalties, data breach notifications, and reputational damage. Ensuring proper authentication is critical for maintaining compliance.

Mitigation Strategies

Upgrade to version 1.0.12 or later. If unable to upgrade, set $ESPHOME_USERNAME and $ESPHOME_PASSWORD to the same values as the legacy credentials. Alternatively, restrict dashboard port access to trusted networks only.

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