==========================================================================
Ubuntu Security Notice USN-3493-1
November 27, 2017

exim4 vulnerability
==========================================================================

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

- Ubuntu 17.10
- Ubuntu 17.04

Summary:

Exim could be made to crash or run programs if it received specially
crafted network traffic.

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

Details:

It was discovered that Exim incorrectly handled memory in the ESMTP
CHUNKING extension. A remote attacker could use this issue to cause Exim to
crash, resulting in a denial of service, or possibly execute arbitrary
code. The default compiler options for affected releases should reduce the
vulnerability to a denial of service.

Update instructions:

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

Ubuntu 17.10:
  exim4-daemon-heavy              4.89-5ubuntu1.1
  exim4-daemon-light              4.89-5ubuntu1.1

Ubuntu 17.04:
  exim4-daemon-heavy              4.88-5ubuntu1.2
  exim4-daemon-light              4.88-5ubuntu1.2

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

References:
  https://www.ubuntu.com/usn/usn-3493-1
  CVE-2017-16943

Package Information:
  https://launchpad.net/ubuntu/+source/exim4/4.89-5ubuntu1.1
  https://launchpad.net/ubuntu/+source/exim4/4.88-5ubuntu1.2