This week (Thursday the 4th), SQL 2016 SP1 CU7 was released. Right, fine, nothing out of the ordinary.
Except there is something out of the ordinary here. CU7 includes the patches for SQL Server related to the Spectre and Meltdown vulnerabilities (for more info on these as they relate to SQL Server, see Joey’s post here and Allen’s post here), and as a result, it is being flagged and published as a security update from Microsoft as KB 4058561.
Since this is a security update, that means it will be pushed down by/via Windows Update like other normal security patches. 4058561 says that, “This update will be provided via Microsoft Update at a future date”, but it’s probably safe to assume that this “future date” will be next Tuesday, January 9th, as that is the normal Patch Tuesday this month.
All that said, then, if you are or support a shop that likes to test their SQL CUs before they get deployed, if there aren’t also positive controls on what Windows Update does, it will be a good idea to start testing this update now. Sure, the Venn diagram of “people who test CUs” and “people who let Windows Update go to town on their SQL Servers, whether it be right off the bat Tuesday night or on the next weekend” probably don’t overlap much, but in case you fall into that category: Heads up.
Remember that CUs include all patches since their “baseline” (in this case, SP1), so you’re not going to just be getting the most recent updates–you’re going to be getting an additional six CUs’ worth, too.
Once again, as everyone else is (or should be) saying, this is a big-deal security vulnerability, and you (all of you, yes, even YOU) really need to apply this patch. For SQL Servers, see guidance from MS here: https://support.microsoft.com/en-us/help/4073225/guidance-for-sql-server
Seriously… patch your stuff.