The Meltdown and Spectre flaws—two related vulnerabilities that enable a wide range of information disclosure from every mainstream processor, with particularly severe flaws for Intel and some ARM chips—were originally revealed privately to chip companies, operating system developers, and cloud computing providers. That private disclosure was scheduled to become public some time next week, enabling these companies to develop (and, in the case of the cloud companies, deploy) suitable patches, workarounds, and mitigations.
With researchers figuring out one of the flaws ahead of that planned reveal, that schedule was abruptly brought forward, and the pair of vulnerabilities was publicly disclosed on Wednesday, prompting a rather disorderly set of responses from the companies involved.
There are three main groups of companies responding to the Meltdown and Spectre pair: processor companies, operating system companies, and cloud providers. While the response to Meltdown and Spectre hasn't been as smooth as originally hoped, vendors appear to have done a thorough job. Meltdown, though easier to exploit, is also easier to protect against; the operating system changes appear successful and should do a solid job for the Intel, Apple, and future ARM chips that are susceptible to the attack.
Spectre, however, is going to be a trickier customer. It doesn't have any clean, simple fix. Operating system changes, ideally in conjunction with greater hardware control over branch prediction, will provide protection in some scenarios, but the array-bounds version of Spectre is going to require careful examination of, and repair to, vulnerable applications. Unlike the other attacks, there doesn't appear to be any way of implementing an operating system-level fix, and the application of appropriate application-level fixes is in all likelihood going to require lots of manual effort by developers.