A polkit security update has been released for Ubuntu Linux 20.04 LTS, 20.10, and 21.04.

==========================================================================
Ubuntu Security Notice USN-4980-1
June 03, 2021

policykit-1 vulnerability
==========================================================================

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

- Ubuntu 21.04
- Ubuntu 20.10
- Ubuntu 20.04 LTS

Summary:

The system could be made to run programs as an administrator.

Software Description:
- policykit-1: framework for managing administrative policies and privileges

Details:

Kevin Backhouse discovered that polkit incorrectly handled errors in the
polkit_system_bus_name_get_creds_sync function. A local attacker could
possibly use this issue to escalate privileges.

Update instructions:

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

Ubuntu 21.04:
libpolkit-agent-1-0 0.105-30ubuntu0.1
libpolkit-gobject-1-0 0.105-30ubuntu0.1
policykit-1 0.105-30ubuntu0.1

Ubuntu 20.10:
libpolkit-agent-1-0 0.105-29ubuntu0.1
libpolkit-gobject-1-0 0.105-29ubuntu0.1
policykit-1 0.105-29ubuntu0.1

Ubuntu 20.04 LTS:
libpolkit-agent-1-0 0.105-26ubuntu1.1
libpolkit-gobject-1-0 0.105-26ubuntu1.1
policykit-1 0.105-26ubuntu1.1

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-4980-1
CVE-2021-3560

Package Information:
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-30ubuntu0.1
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-29ubuntu0.1
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-26ubuntu1.1