[junto]

Well there are two possible scenarios I can envisage.

  a) The issue was an oversight and simply a bug that needs
     to be fixed. The question is why FB doesn't want it 
     fixed?
  b) Moxie knew that this issue existed but was NDA'ed into
     leaving it there for nefarious purposes. Now it's public 
     knowledge, where do we go from here?

[mysticmarvel]

This exploit is not in the original Signal protocol, and was introduced by WhatsApp. Signal discards undelivered messages when the encryption key changes, WhatsApp implemented re-transmission because they think it improves usability. It does do that, and it also introduces this security risk.

It says so right in the article. Stop spreading FUD.

[antihero]

Moxie endorsed Whatsapp, though. We view Moxie as a trusted actor, so either he is untrustworthy which would SUCK or he didn't know that they did this.

[vonklaus]

If one of those was fact I would guess "a".