USN-3934-1: PolicyKit vulnerability

3 April 2019

policykit-1 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


PolicyKit could allow unintended access.

Software Description

  • policykit-1 - framework for managing administrative policies and privileges


It was discovered that PolicyKit incorrectly relied on the fork() system call in the Linux kernel being atomic. A local attacker could possibly use this issue to gain access to services that have cached authorizations.

Update instructions

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

Ubuntu 18.10
libpolkit-backend-1-0 - 0.105-21ubuntu0.4
policykit-1 - 0.105-21ubuntu0.4
Ubuntu 18.04 LTS
libpolkit-backend-1-0 - 0.105-20ubuntu0.18.04.5
policykit-1 - 0.105-20ubuntu0.18.04.5
Ubuntu 16.04 LTS
libpolkit-backend-1-0 - 0.105-14.1ubuntu0.5
policykit-1 - 0.105-14.1ubuntu0.5
Ubuntu 14.04 LTS
libpolkit-backend-1-0 - 0.105-4ubuntu3.14.04.6
policykit-1 - 0.105-4ubuntu3.14.04.6

To update your system, please follow these instructions:

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