Facebook could be headed into a major privacy row as a design flaw in its Messenger Kids app has been found allowing strangers to connect with children. The app mandates parents to approve whom their child interacts with. However, a loophole allowed children to enter group chats with unapproved users, The Verge reports. A child's friend could create a group chat and add his side of parent-approved friends, creating a complex equation where the participants may not be known to each other. Since the discovery of the 'technical error', Facebook has been quietly alerting users and shutting down such group chats. The bug is due to the way the permissions are applied to a group chat.