Security Advisory: Physical UART Access Leading to an Unauthenticated Root Shell in Kasa EC70 and EC71 (CVE-2026-102370)

Vulnerability Description and Impact

CVE-2026-102370: Physical UART Access Leading to an Unauthenticated Root Shell

Kasa EC70 v4 and EC71 v4 do not logically disable the production debug interface at the firmware or chip level and do not lock the bootloader. Although the debug traces are physically severed during manufacturing, an attacker with physical access can restore the connection, interrupt the boot process, and manipulate boot parameters to enter a non-standard initialization path that exposes an unauthenticated root shell during startup.

Successful exploitation may allow an attacker with physical access to obtain root-level command access during device startup, resulting in loss of confidentiality, integrity, and availability for the affected device. Exploitation requires device disassembly, restoration of the severed debug connection, and manipulation of the boot process.

CVSS v4.0 Score: 5.4 / Medium

CVSS:4.0/AV:P/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Affected Products/Versions and Fixes:

Recommendations:

We strongly recommend that users with affected devices take the following actions:

1. Follow the instructions to update to the latest firmware version:

US: Download for EC70 | TP-Link

Download for EC71 | TP-Link

Disclaimer:

This advisory is provided for informational purposes only and is subject to change without notice. The information is provided “as is” without warranties of any kind. TP-Link recommends that customers promptly apply available firmware updates or implement documented workarounds as provided in this advisory. Devices/systems that are not updated or mitigated as described may remain vulnerable, and TP-Link disclaims any responsibility or liability for any damages or losses arising from a failure to implement such updates.