Cannot display map on OpenStreetMap home page due to CSP violation

I didn't use OpenStreetMap for a while, but when I'm trying to browse the map today, it completely failed to load in my browser; the first error indicated by web page console is 'Content Security Policy: The page’s settings blocked the loading of a resource at self (“script-src”). Source: call to eval() or related function blocked by CSP.'

I'm using Firefox 60.9.0esr-1~deb9u1 from Debian.

Any idea of the cause?