We have recently had a case of a file upload failure on a Drupal 7 site on which we have not performed recent updates that would have caused a failure, when uploading a file an error message like the following appears.
Testing with other browsers we noticed that the bug was not present, this indicated a likely browser related bug and not a change we had made.
Researching recent Chrome updates, we found that version 83 had been released only a few days ago which coincided with the dates of the bug.
Researching similar ported cases we found that something along the same lines had already been mentioned on the Drupal.org forums.
For Drupal 8: https://www.drupal.org/project/drupal/issues/3138421
For Drupal 7: https://www.drupal.org/project/drupal/issues/3143016
In summary the flaw is with Jquery Form which is used by the administrative environment for file uploads, the library has an implementation that was discontinued in this version of Chrome and is the cause of the bug.
We see that there is affectation in both Drupal 7 and Drupal 8 but both cases there are also patches available to deploy.
A bit more details of the case are described in the Jquery Form project issue.
