USN-4134-3: IBus vulnerability

24 March 2020

ibus vulnerability

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

  • Ubuntu 19.10
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS


IBus could allow local users to capture key strokes of other locally logged in users.

Software Description

  • ibus - Intelligent Input Bus - core


USN-4134-1 fixed a vulnerability in IBus. The update caused a regression in some Qt applications and the fix was subsequently reverted in USN-4134-2. The regression has since been resolved and so this update fixes the original vulnerability.

We apologize for the inconvenience.

Original advisory details:

Simon McVittie discovered that IBus did not enforce appropriate access controls on its private D-Bus socket. A local unprivileged user who discovers the IBus socket address of another user could exploit this to capture the key strokes of the other user.

Update instructions

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

Ubuntu 19.10
ibus - 1.5.21-1~exp2ubuntu2.1
Ubuntu 18.04 LTS
ibus - 1.5.17-3ubuntu5.3
Ubuntu 16.04 LTS
ibus - 1.5.11-1ubuntu2.4

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.