Modern c++ can be as safe as any language given rigorous guidelines and methods. But X project put together with "programmers off the street" is likely to involve some portion of crashes through sloppy coding.
The thing is that you have to clarify safety and danger. In more application than people would like to acknowledge, slowing down to the point of unusability can be as much of a dangerous result as crashing with a null pointer. Slowness has been standard quality of Python and Ruby development as much as null pointers have been a standard quality of c/c++ development. Either can be avoided with proper care but these all somewhat different failure modes.
The one thing is that c++ do present a different kind of security risk than Ruby/Python slow-downs or even Ruby/Python crashes. Despite this, a some point you still have to consider the tradeoffs.
The thing is that you have to clarify safety and danger. In more application than people would like to acknowledge, slowing down to the point of unusability can be as much of a dangerous result as crashing with a null pointer. Slowness has been standard quality of Python and Ruby development as much as null pointers have been a standard quality of c/c++ development. Either can be avoided with proper care but these all somewhat different failure modes.
The one thing is that c++ do present a different kind of security risk than Ruby/Python slow-downs or even Ruby/Python crashes. Despite this, a some point you still have to consider the tradeoffs.