Canonical has pushed a security update to all major Ubuntu versions. The update fixes an important security vulnerability affecting Ubuntu 12.04 LTS, 14.04 LTS, 16.04 LTS and 16.10 LTS.
The bug could allow an attacker to crash the system or run programs using root access. The vulnerability was discovered within xfrm framework used for transforming packets in Linux kernel. It could execute arbitrary code with administrator access to cause denial of service attacks.
Canonical has additionally fixed the validation issue in xfrm framework. There are new kernel versions in stable repositories for all affected Ubuntu versions. The release has been tested and optimized for various hardware architectures as well.
The Ubuntu maker has published new generic kernel images in stable repositories. Ubuntu 12.04 LTS users can download linux-image 188.8.131.52.140, Ubuntu 14.04 LTS users can download linux-image 184.108.40.206.125, Ubuntu 16.04 LTS users can download linux-image 220.127.116.11.77 and Ubuntu 16.10 LTS users can download linux-image 18.104.22.168.57.
Users can update their kernels from Software Updater Utility from Unity Dash or directly using terminal.