CVE-2026-23833 is an integer overflow vulnerability in ESPHome versions 2025.9.0 through 2025.12.6, specifically within the API component's protobuf decoder, affecting all ESPHome device platforms. This flaw allows unauthenticated denial-of-service attacks when API encryption is not utilized, causing devices to crash by reading invalid memory. With a CVSS score of 7.5 (HIGH), the vulnerability is easily exploitable over the network with low attack complexity and no user interaction required. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE. Users are advised to upgrade to ESPHome 2025.12.7 or later, enable API encryption, and adhere to security best practices.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 2025.9.0, < 2025.12.7CPE matchmatch criteria | cpe:2.3:a:esphome:esphome:*:*:*:*:*:*:*:* |
CVSS version used by this source: 4.0
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
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The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.