The No Knowledge design of all of our products means that your backed up files, stored messages, and stored passwords are encrypted on your computer before being transmitted to or stored with us, and the only key to decrypt them is held by you. Even if someone were to somehow obtain our copy of your data, it is encrypted and we don't have the key. For that reason, your data on our servers is as safe as ever.
It is sadly true that nearly every computer in the world is affected by the Meltdown and Spectre vulnerabilities. For our part we are applying patches on our computers as fast as they become available, albeit in a way that does not affect end user uptime. You should update your computers as well.
The day the vulnerabilities were publicly announced, we did a Firewall Chat on the subject which we recommend.