I was greeting with an interesting dialog box when I got back to my computer just now:
I did some digging and it turns out that WPF did have a vulnerability, but it was patched a couple of days ago. Firefox, however, has no way of knowing if you’re running the patched version or the original one with a security flaw (which Microsoft forcibly added to Firefox without warning a few months ago). You can read more about the issue here.
Interesting times huh?