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.
Exploitability
AV:AAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:N8.1/CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NOther