Yes, at the risk of sounding arrogant, what is this doing on the front page of HN? This isn't a security flaw and it isn't new, it's a well-understood Unix design decision.

If the aim was to educate people about Unix design principles, then it would have been useful to include references to the relevant specifications:

http://pubs.opengroup.org/onlinepubs/9699919799/functions/un...

or at least have some meaningful discussion about the rationale for this design and its consequences. But this is just a statement of well-known fact with no context or added value, placed behind a link-bait title.