14 DAY TRIAL // Canonical published details a couple of days ago, in a security notice, about an HAProxy problem that was identified and fixed for its Ubuntu 15.04 and Ubuntu 14.10 operating systems.
According to Canonical, HAProxy could be made to expose sensitive information over the network. This is a load balancing reverse proxy, so it's not really a major issue. Nonetheless, it would be a good idea to upgrade the system as soon as possible.
"It was discovered that HAProxy incorrectly handled certain buffers. A remote attacker could possibly use this issue to obtain sensitive information belonging to previous requests," reads the entry for this vulnerability.
For a more detailed description of the security problems, you can visit Canonical's security notification. The security flaws can be fixed if you upgrade your system(s) to the latest HAProxy package, specific to each operating system. To apply the update, run the Update Manager application.
You can also upgrade the system from the terminal. Just enter these commands in a terminal near you (root is needed to complete the process):
sudo apt-get dist-upgrade