Apple Warns About Third-Party Keyboard Issue in iOS 13 and iPadOS, Fix Coming Soon
Third-party keyboards can be set to run standalone without access to external services or can request "full access" to provide additional features. A bug in iOS 13 and iPadOS can cause keyboard extensions to be granted full access even if full access hasn't been approved.
According to Apple, the bug does not affect Apple's built-in keyboards, nor does it impact keyboards that don't make use of full access.
Third-party keyboard extensions in iOS can be designed to run entirely standalone, without access to external services, or they can request "full access" to provide additional features through network access. Apple has discovered a bug in iOS 13 and iPadOS that can result in keyboard extensions being granted full access even if you haven't approved this access.
Apple says that the bug will be fixed in an upcoming software update. Third-party keyboards that you might have installed can be viewed by opening up the Settings app, and then going to General > Keyboard > Keyboards.
iOS users concerned about their data and the access granted to third-party keyboards can mitigate the issue by temporarily uninstalling third-party keyboards.