ESPHome vulnerable to denial-of-service via out-of-bounds check bypass in the API component

ESPHome is a system to control microcontrollers remotely through Home Automation systems. In versions 2025.9.0 through 2025.12.6, an integer overflow in the API component's protobuf decoder allows denial-of-service attacks when API encryption is not used. The bounds check `ptr + field_length > end` in `components/api/proto.cpp` can overflow when a malicious client sends a large `field_length` value. This affects all ESPHome device platforms (ESP32, ESP8266, RP2040, LibreTiny). The overflow bypasses the out-of-bounds check, causing the device to read invalid memory and crash. When using the plaintext API protocol, this attack can be performed without authentication. When noise encryption is enabled, knowledge of the encryption key is required. Users should upgrade to ESPHome 2025.12.7 or later to receive a patch, enable API encryption with a unique key per device, and follow the Security Best Practices.

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整数溢出或超界折返

ESPHome 输入验证错误漏洞

ESPHome是ESPHome开源的一个配置、管理智能硬件的系统。用于控制Esp8266/Esp32硬件，实现家庭自动化控制。 ESPHome 2025.9.0版本至2025.12.6版本存在输入验证错误漏洞，该漏洞源于API组件的protobuf解码器存在整数溢出，可能导致绕过越界检查并引发拒绝服务攻击。

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