CVE-2026-23833: PYSEC-2026-1326 - ESPHome vulnerable to denial-of-service via out-of-bounds check bypass in the API component

CVE-2026-23833 · Severity: medium · CVSS 4 · Published 2026-07-07

ESPHome vulnerable to denial-of-service via out-of-bounds check bypass in the API component

Technologies: esphome (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-23833 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-23833 being exploited in the wild.
How severe is CVE-2026-23833?
Medium severity, with a CVSS score of 4, published 7 July 2026.
Which products and versions are affected?
esphome (PyPI) ECOSYSTEM:introduced=2025.9.0,fixed=2025.12.7.
Is there a fix for CVE-2026-23833?
Yes. esphome (PyPI): upgrade to 2025.12.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-23833?
Check whether you run esphome (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • esphome (PyPI): upgrade to 2025.12.7 or later
    pip install "esphome>=2025.12.7"

Affected products

  • esphome (PyPI) ECOSYSTEM:introduced=2025.9.0,fixed=2025.12.7

Identifiers

  • CVE-2026-23833
  • GHSA-4h3h-63v6-88qx
  • PYSEC-2026-1326

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