With version 2.19.20, WhatsApp has increased the security of the messenger. Many users have wanted the screen lock for a long time - but it seems to have a problem.
At the beginning of February, WhatsApp Update 2.19.20 was released - the screen lock for the messenger. For the first time, users could activate the biometric recognition method Touch ID or Face ID as needed and thus protect the content from curious people. Now it turns out that the function contains a serious bug - the authorization can be bypassed very easily. All users who have activated their screen lock but have not set the time period to "immediately" are affected. To be able to bypass the lock, the iOS's own sharing menu is sufficient. Here, the unauthorized person can, for example, go to the "Photos" app and select an image from there, then click on Share on WhatsApp; now all chats are listed - once this step has been taken, the process can be canceled and the app closed. If you now go to WhatsApp directly, you get access to all chat histories without any biometric query.
Better safe than sorry
Again: The process only works if the user has not set the screen lock to "immediately". We have of course tried it out ourselves and can confirm the error. Until WhatsApp has submitted an update to fix the error, this is the only way to ensure protection from prying eyes - insofar as third parties can access an iPhone unnoticed and know the unlock code. Here you can read how the screen lock in WhatsApp is activated.
*Update: The bug was fixed with version 2.19.22
