Is my site affected?

Each flaw on this tracker says who it touches. These are the places to look for what your site runs.

/wp-admin/
If adding /wp-admin/ to your address brings up a login, the site runs WordPress. WordPress runs on PHP.
Your host’s control panel
In cPanel or Plesk, a page with PHP in its name usually shows the version your site is on.
package.json
A site whose files hold a package.json was built with Node.js, and the packages it lists usually come from npm.
Squarespace, Wix or Shopify
These run the server software for you. Their own status and security pages are where to look.
Still not sure
Ask whoever built the site, or your host, what it runs and which version.

Ask for the patch check