https://motherboard.vice.com/en_us/article/a3nn9g/coinhive-meltdown-monero-mining-cpu

Last week, researchers revealed the existence of Meltdown, one of two major security flaws that affects pretty much every modern computer and could allow attackers to gain access everything on those computers, including passwords and other sensitive personal information. After patches to fix this vulnerability were released, rumors circulated that the patches could significantly degrade a computer’s performance.

While this is concerning for anybody, it could be a big problem for the people who use their CPU—a computer’s “brain”—to mine Monero, the only top 20 cryptocurrency by market cap that supports CPU mining, rather than requiring graphics cards or other specialized hardware. It would also be a serious hit to operations that hijack CPU power from tons of people to turn a profit, like the in-browser mining extension Coinhive or the North Korean university students who apparently created Monero mining malware.