The Sentry kernel is a high security level micro-kernel implementation made for high security embedded systems. A given task with one of the DEV or IO capability is able to interact with another task's IRQ line through the __sys_int_* syscall familly. Prior to version 0.4.7, this can lead to DoS and covert-channels between this task and the outer world. A patch is available in version 0.4.7. As a workaround, reduce tasks that have the DEV and IO capability to a single one.