20 February 2019
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.10
- Ubuntu 18.04 LTS
GDM could give unauthorized access to a different user.
- gdm3 – GNOME Display Manager
Burghard Britzke discovered that GDM incorrectly handled certain configurations.
An attacker could possibly use this issue to get unauthorized access to
a different user.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make
all the necessary changes.