High 7.5Published Jan 19, 2026

CVE-2026-23833ESPHome is a system to control microcontrollers remotely through Home Automation systems.

Updated under an hour ago (2026-10-19 08:00 UTC)

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Every CVE for esphome

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-190
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

esphome esphome esphome:esphome	from 2025.9.0 before 2025.12.7	NVD

References

https://esphome.io/guides/security_best_practicestechnical-description
https://github.com/esphome/esphome/commit/69d7b6e9210390051318bd8e6410727689de08d6patch
https://github.com/esphome/esphome/pull/13306issue-tracking, patch
https://github.com/esphome/esphome/security/advisories/GHSA-4h3h-63v6-88qxmitigation, patch, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.