A set top box or like device incorporating an untrusted software framework as a client of a secure operating system kernel. The software framework may comprise, for example, an Android framework supported by an underlying Linux operating system environment having a secure kernel. The software framework can be executed using a variety of process isolation techniques depending on performance and isolation requirements. A secure access client/server interface may also be provided to support interactions between the untrusted software framework (and applications utilizing the untrusted software framework) and secure or trusted portions of the device. The secure access interface can be configured to perform operations such as handle validation, heap pointer validation, non-pointer parameter validation, heap isolation, and resource release relating to terminated processes. In further embodiments, a software framework aggregator is used to support a plurality of additional software frameworks for use in the set top box.