Can't upload files in Safari 18.1

I saw someone else ask about this, but the topic was closed. Posting for those who still run into this.

The issue:

Dropbox, AWS, or any other website where you would hit "upload" and get the finder window to choose a file or folder, does not work. Safari freezes up, and eventually just comes back to the page you were on.

The fix:

Check your extensions, and update any that might be out of date.

Macbook M3, MacOS Sequoia 15.1, Safari 18.1