=========================================================================Ubuntu Security Notice USN-4075-1
July 25, 2019

exim4 vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Exim could be made to run programs as an administrator if it received
specially crafted network traffic.

Software Description:
- exim4: Exim is a mail transport agent

Details:

Jeremy Harris discovered that Exim incorrectly handled sort expansions. In
environments where sort expansions are used, a remote attacker could
possibly use this issue to execute arbitrary code as root.

Update instructions:

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

Ubuntu 19.04:
  exim4-daemon-heavy              4.92-4ubuntu1.2
  exim4-daemon-light              4.92-4ubuntu1.2

Ubuntu 18.04 LTS:
  exim4-daemon-heavy              4.90.1-1ubuntu1.3
  exim4-daemon-light              4.90.1-1ubuntu1.3

Ubuntu 16.04 LTS:
  exim4-daemon-heavy              4.86.2-2ubuntu2.4
  exim4-daemon-light              4.86.2-2ubuntu2.4

In general, a standard system update will make all the necessary changes.

References:
  
  CVE-2019-13917

Package Information:
  https://launchpad.net/ubuntu/+source/exim4/4.92-4ubuntu1.2
  https://launchpad.net/ubuntu/+source/exim4/4.90.1-1ubuntu1.3
  https://launchpad.net/ubuntu/+source/exim4/4.86.2-2ubuntu2.4