A method includes instantiating, in response to a request by an executing application, an input data object with one or more uninitialized fields and traversing a path toward a sink in the executing application to a branching point of the executing application. In response to reaching the branching point, one or more parameters are provided for some or all of the one or more uninitialized fields of the input data object, wherein the one or more parameters were determined prior to beginning of execution of the executing application to cause a branch to be taken by the executing application toward the sink. The path is traversed toward the sink at least by following the branch in the executing application. Apparatus and computer program products are also disclosed.