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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-23833 Detail

Description

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-BT 1.7 LOW
Vector:  CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://esphome.io/guides/security_best_practices GitHub, Inc.
https://github.com/esphome/esphome/commit/69d7b6e9210390051318bd8e6410727689de08d6 GitHub, Inc.
https://github.com/esphome/esphome/pull/13306 GitHub, Inc.
https://github.com/esphome/esphome/security/advisories/GHSA-4h3h-63v6-88qx GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-190 Integer Overflow or Wraparound GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-23833
NVD Published Date:
01/19/2026
NVD Last Modified:
01/19/2026
Source:
GitHub, Inc.