gnome-screensaver 2.14.3, 2.22.2, 2.27.x, 2.28.0, and 2.28.3, when the X configuration enables the extend screen option, allows physically proximate attackers to bypass screen locking, access an unattended workstation, and view half of the GNOME desktop by attaching an external monitor.

gnome-screensaver 2.28.x before 2.28.3 does not properly synchronize the state of screen locking and the unlock dialog in situations involving a change to the number of monitors, which allows physically proximate attackers to bypass screen locking and access an unattended workstation by connecting and disconnecting monitors multiple times, a related issue to CVE-2010-0414.

gnome-screensaver 2.28.0 does not resume adherence to its activation settings after an inhibiting application becomes unavailable on the session bus, which allows physically proximate attackers to access an unattended workstation on which screen locking had been intended.

gnome-screensaver before 2.28.2 allows physically proximate attackers to bypass screen locking and access an unattended workstation by moving the mouse position to an external monitor and then disconnecting that monitor.