There's a lot of public evidence of NetFlix's use of FreeBSD and their desire to generally stay up-to-date. I'm not aware of any credible statement that they're actually on -CURRENT though, and even if they were at some point they may not have updated since then.

They are heavily involved in FreeBSD development and I'm sure they're keeping on top of developments in -CURRENT, but I believe they are not using affected versions anywhere in production.