The login endpoint on the Mira cloud API accepts any format-valid string in the password field and returns a live active session token for the account matching the supplied email address. An attacker could use an email address to control cloud accounts and access hormone record information and account settings.
Users should update the Mira app to the latest version iOS v3.5.18 / Android v4.5.18. Firmware v01.07.01.53 is updated via the app when the device is connected. No additional action is required.