Description
ESPHome is a system to control microcontrollers remotely through Home Automation systems. In version 2025.8.0 in the ESP-IDF platform, ESPHome's web_server authentication check can pass incorrectly when the client-supplied base64-encoded Authorization value is empty or is a substring of the correct value. This allows access to web_server functionality (including OTA, if enabled) without knowing any information about the correct username or password. This issue has been patched in version 2025.8.1.
Affected products
esphome: esphome firmware
References3
- github.com/esphome/esphome/security/advisories/GHSA-mxh2-ccgj-8… ExploitVendor Advisory
- github.com/esphome/esphome/security/advisories/GHSA-mxh2-ccgj-8… ExploitVendor Advisory
- github.com/esphome/esphome/commit/2aceb56606ec8afec5f49c92e140c… Patch
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: CNA
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 2% percentile: 75 · as of 8 November 2026
- CWE
- CWE-303
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