Buffer overflow in the XDMCP parsing code of GNOME gdm, KDE kdm, and wdm allows remote attackers to execute arbitrary commands or cause a denial of service via a long FORWARDQUERY request.

libICE in XFree86 allows remote attackers to cause a denial of service by specifying a large value which is not properly checked by the SKIPSTRING macro.

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/.