VitaFit cloud API before 2026-10-30 contained an insecure direct object reference vulnerability that allows authenticated attackers to access another user's data by supplying a different user_id or profile_id to endpoints such as GET /front/profile/{profile_id}/report/ and GET /front/profile/{profile_id}/body_index_per_day/. Attackers can leverage predictable user_id and profile_id relationships combined with an account-enumeration weakness to read another account's email address, profile, body-composition report, and measurement history at scale.