The "Forget about this site" feature in the History pane is intended to remove all saved user data that indicates a user has visited a site. This includes removing any HTTP Strict Transport Security (HSTS) settings received from sites that use it. Due to a bug, sites on the pre-load list also have their HSTS setting removed. On the next visit to that site if the user specifies an `http:` URL rather than secure `https:` they will not be protected by the pre-loaded HSTS setting. After that visit the site's HSTS setting will be restored.
Name: the Mozilla project
Upstream: Thomas Henlich
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2019:2663 https://access.redhat.com/errata/RHSA-2019:2663
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):