USN-3938-1: systemd vulnerability

8 April 2019

systemd vulnerability

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

  • Ubuntu 18.10
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS


The systemd PAM module could be used to gain additional PolicyKit privileges.

Software Description

  • systemd - system and service manager


Jann Horn discovered that pam_systemd created logind sessions using some parameters from the environment. A local attacker could exploit this in order to spoof the active session and gain additional PolicyKit privileges.

Update instructions

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

Ubuntu 18.10
libpam-systemd - 239-7ubuntu10.12
Ubuntu 18.04 LTS
libpam-systemd - 237-3ubuntu10.19
Ubuntu 16.04 LTS
libpam-systemd - 229-4ubuntu21.21
Ubuntu 14.04 LTS
libpam-systemd - 204-5ubuntu20.31

To update your system, please follow these instructions:

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