Can one app read data from clipboard copied in another app
This is not a vulnerability per se.

The clipboard is accessible system wide which is why you can copy something from application A and paste it to application B.

It's not meant nor does it function as a secure holing area.

If an application has sensitive data fields, it is up to the developers to block clipboard access to the data.   For all intents and purposes, once info is in the clipboard, it's accessible.

As a test and demo, copy your password from your password manager.  Open terminal and type the command pbpaste.  It will output the password that's residing in your clipboard.