A LTSP Display Manager security update has been released for Ubuntu Linux 20.04 LTS.

USN-4533-1: LTSP Display Manager vulnerabilities

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Ubuntu Security Notice USN-4533-1
September 22, 2020

ldm vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS

Summary:

LTSP Display Manager could be made to escalate user privileges.

Software Description:
- ldm: LTSP display manager

Details:

Veeti Veteläinen discovered that the LTSP Display Manager (ldm)
incorrectly handled user logins from unsupported shells. A local attacker
could possibly use this issue to gain root privileges. (CVE-2019-20373)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS:
ldm 2:2.18.06-1+deb10u1build0.20.04.1
ldm-server 2:2.18.06-1+deb10u1build0.20.04.1

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4533-1
  https://launchpad.net/bugs/1839431

Package Information:
  https://launchpad.net/ubuntu/+source/ldm/2:2.18.06-1+deb10u1build0.20.04.1