GNOME GDM 2.8, 2.12, 2.14, and 2.15, when the "face browser" feature is enabled, allows local users to access the "Configure Login Manager" functionality using their own password instead of the root password, which can be leveraged to gain additional privileges.
Race condition in daemon/slave.c in gdm before 2.14.1 allows local users to gain privileges via a symlink attack when gdm performs chown and chgrp operations on the .ICEauthority file.
The GDM daemon in GNOME Display Manager (GDM) before 2.14.13, 2.16.x before 2.16.7, 2.18.x before 2.18.4, and 2.19.x before 2.19.5 does not properly handle NULL return values from the gstrsplit function, which allows local users to cause a denial of service (persistent daemon crash) via a crafted command to the daemon's socket, related to (1) gdm.c and (2) gdmconfig.c in daemon/, and (3) gdmconfig.c and (4) gdmflexiserver.c in gui/.