https://www.developer-tech.com/news/2018/may/22/fourth-meltdown-spectre-variant-spotted/

Bad news, everyone. If you thought we were out of the woods when it comes to the Meltdown / Spectre CPU security flaws, then think again. Researchers from Microsoft and Google have identified a previously unknown fourth variant of the processor design issues that made front page news when they were discovered last year.

Like its predecessors, variant 4 (or CVE-2018-3639, to give its full name) describes a processor design issue that could allow malicious software to discover hidden information, such as a user's password. For example, a webpage set up by a malware programmer could discover passwords, credit card numbers and other private information input elsewhere in the same browser.