It’s a bit arguing about semantics really. But Rust and Haskell are merely the first ones with patches out. The issue affects other languages as well, including Java, Node.js, Python and seemingly every language with Windows support. I think it’s fair to call it a Windows problem, since it affects everyone there.
But languages like Rust and Haskell are promising their users that they are protected from this kind of behavior, which is why they want to patch it quickly. Some of the others merely updated the documentation, effectively saying yeah it’s a risk. Java went as far as saying they won’t fix the issue.