GNOME Display Manager (gdm) before 2.21.1 allows local users to change permissions of arbitrary directories via a symlink attack on /tmp/.X11-unix/.
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=988498
http://secunia.com/advisories/54661
http://rhn.redhat.com/errata/RHSA-2013-1213.html
Source: Mitre, NVD
Published: 2013-09-10
Updated: 2013-09-12
Base Score: 6.9
Vector: CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C
Severity: Medium
Base Score: 8.1
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: High