Modern Greek doesn't have the French "u" sound, I don't know if ancient Greek did. The "υ" in "κυβερνήτης" (cybernetes/kubernetes = helmsman, governor) is pronounced "i", as in "miss".
Incidentally, the word "governor" comes from "kubernetes" as well.
In the IPA, the sound of the French 'u' or German 'ü' is written with as 'y'. E.g. French "tu" -> [ty].
To speakers of languages without that sound, it often gets mapped to the vowel sound in the English word "loose".
So you can see what's happened here, "cybernetics" with the "Greek 'y'" pronounced as French "u" becomes "kubernetes".
I don't know if modern Greek still has that sound.
I love little realisations like this. Sometimes I wish I'd done linguistics instead of computer science.