You can always check that Windows Security is up to date on your Windows device, via Windows Update. If you want to know what the latest security updates are, or you think you might need to install an update manually, Microsoft keeps an online list called the Security Update Guide.
The Security Update Guide is a single resource for finding (and manually downloading) the latest Windows Security updates. It initially previewed back in 2016. The Microsoft Security Update Guide can be found at the Microsoft Security Response Center (MSRC).