Broken Access Control Leading to Cross-Device Token Issuance in Tapo Cloud MQTT Proxy

The Tapo
Cloud MQTT broker contains a broken access control vulnerability in a proxy
topic used by authenticated Tapo devices to request service tokens. The broker
does not verify that the device ID supplied in a proxy request belongs to the
authenticated device. An attacker who owns a Tapo device and knows another
device's ID may obtain a device token scoped to the target device and use it to
upload attacker-controlled content to the target user's Tapo Cloud storage. The
content may then be presented in the Tapo app as a legitimate event.

Successful
exploitation may allow an attacker to upload attacker-controlled content that
is presented to a target user as a legitimate Tapo event, retrieve internal
service information through crafted proxy requests, or abuse Tapo Cloud
outbound request capability in activity that could affect service
availability.