GNOME Shell provides core user interface functions for the GNOME 3 desktop, like switching to windows and launching applications.
It was discovered that GNOME Shell incorrectly handled the login screen password dialog.
Please review the referenced CVE identifiers for details.
There is no known workaround at this time.
All GNOME Shell users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=gnome-base/gnome-shell-3.34.5-r1"