In Octopus Deploy 2019.1.0 through 2019.3.1 and 2019.4.0 through 2019.4.5, an authenticated user with the VariableViewUnscoped or VariableEditUnscoped permission scoped to a specific project could view or edit unscoped variables from a different project. (These permissions are only used in custom User Roles and do not affect built in User Roles.)