"The problem lay in a private application programming interface (the slice of code allowing certain outside access) that wasn’t properly checking the person deleting the comment was the same one who posted it, the spokesperson added."

http://www.forbes.com/sites/thomasbrewster/2016/05/03/facebo...

I'm hoping the bug was a little more complicated than just "we forgot to check." That's a pretty dumb mistake to make...

Do you see how the PS3 security system was thwarted?[1]

1: http://www.engadget.com/2010/12/29/hackers-obtain-ps3-privat...

Yes, dumb mistakes happen often, but that doesn't make them not dumb.