Integer Overflow or Wraparound Affecting esphome package, versions [2025.9.0,2025.12.7)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Integer Overflow or Wraparound vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-PYTHON-ESPHOME-15038611
- published20 Jan 2026
- disclosed19 Jan 2026
- creditMat931
Introduced: 19 Jan 2026
CVE-2026-23833 (opens in a new tab)How to fix?
Upgrade esphome to version 2025.12.7 or higher.
Overview
esphome is a Make creating custom firmwares for ESP32/ESP8266 super easy.
Affected versions of this package are vulnerable to Integer Overflow or Wraparound via the protobuf decoder in the API component. An attacker can cause the device to read invalid memory and crash by sending a maliciously crafted large field_length value, which triggers an integer overflow and bypasses the out-of-bounds check. This can be exploited remotely without authentication when API encryption is not enabled.
Note:
This is only exploitable if API encryption is disabled or, if enabled, the attacker possesses the encryption key.
Workaround
This vulnerability can be mitigated by enabling API encryption with a unique key per device.