CVE-2026-23833
Description
A flaw was found in ESPHome. An integer overflow vulnerability exists in the API component's protobuf decoder. A remote attacker can exploit this by sending a specially crafted, large field_length value, which bypasses a bounds check. This can lead to a denial-of-service (DoS) condition, causing the affected device to crash. This attack can be performed without authentication if API encryption is not utilized.
Statement
This vulnerability is rated Low for Red Hat. The flaw in ESPHome's API component, affecting python-aioesphomeapi in Fedora 42, can lead to a denial of service. Exploitation requires the API encryption to be disabled; if encryption is enabled, knowledge of the encryption key is necessary.
Mitigation
To mitigate this issue, enable API encryption with a unique key for each ESPHome device. This prevents unauthenticated denial-of-service attacks by requiring knowledge of the encryption key for exploitation. Refer to ESPHome's Security Best Practices for detailed configuration instructions.
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