USN-3255-1: LightDM vulnerability

4 April 2017

lightdm vulnerability

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

  • Ubuntu 16.10
  • Ubuntu 16.04 LTS


LightDM could be made to run programs as an administrator.

Software Description

  • lightdm - Display Manager


It was discovered that LightDM incorrectly handled home directory creation for guest users. A local attacker could use this issue to gain ownership of arbitrary directory paths and possibly gain administrative privileges.

Update instructions

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

Ubuntu 16.10
lightdm - 1.19.5-0ubuntu1.1
Ubuntu 16.04 LTS
lightdm - 1.18.3-0ubuntu1.1

To update your system, please follow these instructions:

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