As per the recent post on the Apple Support, dated September 13, 2021, Apple has released a new update for the Safari web browser that includes important new security fixes. Safari is built using Apple WebKit, which has a vulnerability know to allow malicious web content to execute unauthorized code on your computer.
We advise you update Safari on all computer and devices, at home and at work, (campus and personal) before you use them to access webpages.
For information on how to update Safari on an Mac, see the Apple Support page page, Update or reinstall Safari for your computer. If you are using Safari on Windows, please discontinue use and uninstall Safari. Apple Safari for Windows is on longer supported by Apple. Access webpages only from web browsers that are supported and receive security updates.