Subject: [ASA-202011-5] gdm: privilege escalation

Arch Linux Security Advisory ASA-202011-5
=========================================

Severity: High
Date    : 2020-11-10
CVE-ID  : CVE-2020-16125
Package : gdm
Type    : privilege escalation
Remote  : No
Link    : https://security.archlinux.org/AVG-1264

Summary
=======

The package gdm before version 3.38.2-1 is vulnerable to privilege
escalation.

Resolution
==========

Upgrade to 3.38.2-1.

# pacman -Syu "gdm>=3.38.2-1"

The problem has been fixed upstream in version 3.38.2.

Workaround
==========

None.

Description
===========

gdm before 3.38.2 can be tricked into launching gnome-initial-setup,
enabling an unprivileged user to create a new user account for
themselves. The new account is a member of the sudo group, so this
enables the unprivileged user to obtain admin privileges.

Impact
======

An unprivileged local user might be able to elevate privileges to root.

References
==========

https://gitlab.gnome.org/GNOME/gdm/-/issues/642
https://security.archlinux.org/CVE-2020-16125