A sddm security update has been released for Debian GNU/Linux 9 LTS to address an issue in the sddm display manager where local unprivileged users could create a connection to the X server.

DLA 2436-1: sddm security update

- -------------------------------------------------------------------------
Debian LTS Advisory DLA-2436-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Chris Lamb
November 06, 2020   https://wiki.debian.org/LTS
- -------------------------------------------------------------------------

Package : sddm
Version : 0.14.0-4+deb9u2
CVE ID : CVE-2020-28049
Debian Bug : #973748

It was discovered that there was an issue in the sddm display manager
where local unprivileged users could create a connection to the X
server.

For Debian 9 "Stretch", this problem has been fixed in version
0.14.0-4+deb9u2.

We recommend that you upgrade your sddm packages.

For the detailed security status of sddm please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/sddm

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://wiki.debian.org/LTS