The latest WhatsApp bug resided in WhatsApp’s implementation of XMPP communication protocol that crashes the app when a member with invalid phone number drops a message in the group. An attacker can trigger a fully-destructive WhatsApp crash-loop forcing all group members to completely uninstall the app, reinstall it, and remove the group to regain normal function. The company patched the issue with the release of WhatsApp version 2.19.58 in mid-September. The attack requires a malicious group member to manipulate other parameters associated with messages in a conversation otherwise protected using end-to-end encryption.
Source: https://thehackernews.com/2019/12/whatsapp-group-crash.html