Real-time embedded systems have to meet a combination of requirements that are in deep tension: they are expected to deliver timely results, observing strict deadlines, all using only very limited resources, computing power and energy. To this day, the most common programming language in this environment is C/C++ because of its zero-cost abstractions and fine control over memory layout. With the upcoming communication ability through network interfaces, an additional requirement gained in importance: security.
Unfortunately, C/C++ supports some secure software design principles only rudimentary. Too many very severe vulnerabilities are directly related to the fact that C/C++ does not guarantee memory safety. To exemplify this, the prominent Heartbleed vulnerability is discussed in terms of causes, technical details and impact.