I took a short look at this and it appears to be a work in progress that varies between browsers...
Chrome implements a "clipboard-read" permission that can be requested by calling navigator.clipboard.read(). When a page calls that it will display a permission request dialog (like those asking for permission to show notifications on seemingly every single news web page). A little clipboard icon will also appear in the nav bar showing the status of the permission (visible after a read attempt is made during that visit)
Firefox is apparently on track as well, although for now the clipboard.read function is not implemented for pages and can only be called by extensions. I'm not sure what the permission dialog for extensions is like.
So... it may be safe. But it is a work in progress and each browser is different. I've only checked the most well-documented method for reading the clipboard... maybe there is some other half-implemented feature or event listener that happens to leak some clipboard data...
Chrome implements a "clipboard-read" permission that can be requested by calling navigator.clipboard.read(). When a page calls that it will display a permission request dialog (like those asking for permission to show notifications on seemingly every single news web page). A little clipboard icon will also appear in the nav bar showing the status of the permission (visible after a read attempt is made during that visit)
Firefox is apparently on track as well, although for now the clipboard.read function is not implemented for pages and can only be called by extensions. I'm not sure what the permission dialog for extensions is like.
https://developer.mozilla.org/en-US/docs/Web/API/Clipboard_A...
So... it may be safe. But it is a work in progress and each browser is different. I've only checked the most well-documented method for reading the clipboard... maybe there is some other half-implemented feature or event listener that happens to leak some clipboard data...