lightdm before 0.9.6 writes in .dmrc and Xauthority files using root permissions while the files are in user controlled folders. A local user can overwrite root-owned files via a symlink, which can allow possible privilege escalation.
https://www.securityfocus.com/bid/50506
https://security-tracker.debian.org/tracker/CVE-2011-3349
https://seclists.org/oss-sec/2011/q3/393
https://bugs.launchpad.net/debian/+source/lightdm/+bug/834079
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=639151
Source: Mitre, NVD
Published: 2019-11-19
Updated: 2019-12-03
Base Score: 7.2
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C
Severity: High
Base Score: 7.8
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.00051