Removing fake Media Flash Player virus in March 2020??

1. Click  menu in the menu bar, hold the  shift key on the keyboard down and choose “Force Quit Safari” from the dropdown.

    Safari will quit.

    Launch Safari holding the shift key down.

    For more info: Pop-ups and ads in Safari: https://support.apple.com/en-us/HT203987

2. Check for adware.

     Run the latest release of Malwarebytes for Mac to remove malware/adware, if installed on your Mac.

     For instructions: Install Malwarebytes for Mac v4      Uninstall Malwarebytes for Mac

     Click the “Scan Now” button. Once done, quit Malwarebytes for Mac.

     Restart the computer and relaunch Safari holding the shift key down.

     Scan for Malware again.

     Remove unknown extensions:  Safari > Preferences > Extensions

     https://support.apple.com/guide/safari/use-safari-extensions-sfri32508/mac

     Reset search engine:    https://support.apple.com/guide/safari/customize-your-search-ibrwe75c2a3c/mac

3. Uninstall Flash Player: https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html

    Install Flash Player if you must have it installed: https://get.adobe.com/flashplayer/

      Download EtreCheck, run it to see if there is any adware installed or not.

      https://etrecheck.com

      Click  “Free download” button,

      Open Downloads folder, click on it to open, and then select ”Open”.

      “Choose a problem” from the popup menu box, and then “Start EtreCheck” in the dialog.

      Click “Share Report” button in the toolbar, select “Copy report” .

      Paste the report when you reply.

      Note: This is a diagnostic test.

I've been getting "Flash Player Update Required" for the past several days on both Safari and Firefox. I do not have Flash installed and neither do others who have gotten the pop-up. It seems to be being generated by some infected sites, so there's nothing you can do to stop it other than closing the window. There's nothing malicious on your Mac. Specifically, CNN seems to a source.

You're welcome, it's a real PITA! Hopefully the infected sites will take steps to block it. If you do download the so-called "update" it will install malware.