CVE-2026-23833

Jan. 19, 2026, 6:16 p.m.

1.7
Low

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.

Product(s) Impacted

Vendor Product Versions
Esphome
  • Esphome
  • 2025.9.0-2025.12.6, *

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-190
Integer Overflow or Wraparound
The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a esphome esphome 2025.9.0-2025.12.6 / / / / / / /
a esphome esphome / / / / / / / es32
a esphome esphome / / / / / / / es8266
a esphome esphome / / / / / / / rp2040
a esphome esphome / / / / / / / libretiny

References

https://esphome.io/guides/security_best_practices
https://github.com/esphome/esphome/commit/69d7b6e9210390051318bd8e6410727689de08d6
https://github.com/esphome/esphome/pull/13306
https://github.com/esphome/esphome/security/advisories/GHSA-4h3h-63v6-88qx

Tags

[email protected]
CWE-190
2026-01-19
CVE-2026-23833

CVSS Score

1.7 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Attack Requirements: PRESENT
  • Privileges Required: NONE
  • User Interaction: NONE
  • Scope:
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: LOW
  • Exploit Maturity: UNREPORTED

    • 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

    View Vector String

Timeline

Published: Jan. 19, 2026, 6:16 p.m.
Last Modified: Jan. 19, 2026, 6:16 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.