There are four critical kernel vulnerabilities (CVE-2015-2925, CVE-2015-5257, CVE-2015-5283, and CVE-2015-7613) that have been addressed in this update. The new kernel packages are 4.2.3-1 for Sid, 3.16.7-ckt11-1+deb8u5 for Jessie, and 3.2.68-1+deb7u5 for Wheezy. All the Debian GNU/Linux operating system that are part of the branches mentioned above are vulnerable, which means that users are urged to update their Debian-based machines as soon as possible using the built-in package management utilities.