A ldm security update has been released for Debian GNU/Linux 8 LTS

Package : ldm
Version : 2:2.2.15-2+deb8u1
CVE ID : CVE-2019-20373
Debian Bug : #948538

It was discovered that a hook script of ldm, the display manager
for the Linux Terminal Server Project incorrectly parsed responses
from an SSH server which could result in local root privilege
escalation.

For Debian 8 "Jessie", this issue has been fixed in ldm version
2:2.2.15-2+deb8u1.

We recommend that you upgrade your ldm packages.

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