This is the real problem. The EU shouldn't allow sale of citizenship in host countries, essentially paying a way to get into the EU. I highly doubt that would be possible to enforce though.
The Cyprus passport scheme has ended this month, only applications submitted before the end of October are considered. The same I believe applies to Malta which had a similar scheme.
it is a hotly debated topic in the EU and seems to be up for removal in the current years, especially in the current political climate.