Yesterday, Adobe announced updates for several of its main products, including Flash, Acrobat Reader, and Shockwave.
Flash 18.104.22.168 addresses five critical vulnerabilities in earlier versions. You can download the new desktop version from the main Flash download page. That page usually offers to install additional software, which you should avoid. Chrome will as usual update itself with the new version, and both Internet Explorer and Edge will get their own updates via Windows Update.
If you use Flash, Reader or Shockwave to view content from untrusted sources, or if you use a web browser with add-ons enabled for any of these technologies, you should update affected systems immediately.