If you’re in the SQL Server world you should be aware of this by now however for those who’ve been busy getting stuff done this week Microsoft have released a security update for SQL Server described in full in KB4583459.
Data can be sent over a network to an affected Microsoft SQL Server instance that might cause code to run against the SQL Server process if a certain extended event is enabled. To learn more about the vulnerability, see CVE-2021-1636.
Patches are available for SQL Server 2012 and above with currently supported service packs. As it’s most people’s best interest to maintain a SQL Server that doesn’t allow this to happen it’s a great idea to get this patch installed now. If you are intending on ruining someone’s day with this exploit I wholeheartedly apologise for spoiling your fun.
I anticipate quite the majority of my clients will “accidentally” end up with this patch through Windows Update which is probably for the better (exceptions given if it somehow kills the SQL Server).