Exim could be made to expose private DKIM signing keys.
Bjoern Jacke discovered that Exim incorrectly handled DKIM keys. In certain configurations, private DKIM signing keys could be leaked to the log files.
5 January 2017
A security issue affects these releases of Ubuntu and its derivatives:
Exim could be made to expose private DKIM signing keys.
Bjoern Jacke discovered that Exim incorrectly handled DKIM keys. In certain configurations, private DKIM signing keys could be leaked to the log files.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.