Add Media button not working in 4.3.1

I have automatically upgraded to 4.3.1, I am running the Twenty-Fourteen theme and all plugins have been disabled. When I click the Add Media button in a post, nothing happens. I’m running Firebug in Firefox, and the page has the following js error:

TypeError: wp.media.view.settings is undefined.

This happens regardless of which theme I switch to (I’ve tried the WP Twenty-Thirteen and Twenty-Fifteen themes as well). I’m also having the same problem with the Insert/Edit Link button in the Visual Editor. Nothing happens when I click it. The other buttons seem to be working fine in the Visual Editor.