Apple users should beware before using third party keyboards. As company has confirmed warning on IOS 13. If apple users are using third party keyboards attacker might have full access. Apple has discovered bug in IOS 13. Third-party keyboards can have full access even if you haven’t granted.
But there will be no harm to Apple built-in keyboards. Apple didn’t give specific details about the flaw. According to Apple the issue will be fixed in next update. If Apple users wants to check what keyboard they are using. For that go to Settings > General > Keyboard > Keyboards
According to ethical hacking researcher of international institute of cyber security this bug can give third-party keyboards like Swiftkey or Gboard gives full access of the phone.