VitaFit Android application (com.vt.vitafit) before 2.8.1.0 contains an insecure custom URI scheme vulnerability that allows a malicious application to intercept Fitbit login tokens by registering the same callback scheme (vitafit://vtio.cn). Attackers can capture the 30-day Fitbit authorization token with weight scope delivered in the callback URL to read, create, and delete the victim's weight and body-fat records via the Fitbit Body API.