Seems like none of these major websites detected anything, and they are supposed to be top-notch in the world.
It's only because the researcher contacted them.
Also because nobody actively exploited them! You're using the word "detected" to mean "discovered", which nobody working in the field would ever do.
Also because nobody actively exploited them! You're using the word "detected" to mean "discovered", which nobody working in the field would ever do.