Ubuntu Security Notice 571-2 – USN-571-1 fixed vulnerabilities in X.org. The upstream fixes were incomplete, and under certain situations, applications using the MIT-SHM extension (e.g. Java, wxWidgets) would crash with BadAlloc X errors. This update fixes the problem.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/62821/USN-571-2.txt
Source: https://packetstormsecurity.com/files/62821/Ubuntu-Security-Notice-571-2.html