CVE-2021-27953

7.5 highEPSS 1.7%

High (7.5) in ecobee ecobee3 lite firmware. EPSS 1.7% chance of exploitation in the next 30 days.

A NULL pointer dereference vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HomeKit Wireless Access Control setup process. A threat actor can exploit this vulnerability to cause a denial of service, forcing the device to reboot via a crafted HTTP request.

Severity

CVSS 3.1

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 1.7% chance of exploitation in the next 30 days; higher than 76% of CVEs (scores of 2026-10-31)
CWE: CWE-476
Published: 2021-08-03
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

ecobee:ecobee3_lite_firmware

References

https://www.l9group.com/advisories/remote-denial-of-service-of-ecobee3-lite
https://www.l9group.com/advisories/remote-denial-of-service-of-ecobee3-lite

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