Abby fuller an Amazon employee might have stumbled upon a WhatsApp that might provide other users your private messages. The potential bug could be exploited when you’re setting up your WhatsApp on a new device with new number it provides an option to restore all the messages from the archives of the previous mobile no owner.
From the official WhatsApp documents it clearly states that any message history of a specific phone no will be deleted after 45 days of inactivity but that doesn’t seem to be the case since Abby has owned the smartphone for more than 45 days and the message history is still present. And while we wait for official statements from WhatsApp other users are also chimed to share their similar experience.
While the above issue might be caused by the phone number is acts as unique identifier of the user ID there are more serious questions to be asked regarding WhatsApp message history storing policy while their own official documents strictly say that they will be deleted with 45 days of inactivity.
Update: Another bug has been found on Whatsapp.