Users are urged to install the new kernel version

Aug 20, 2018 18:25 GMT  ·  By

Last week, Canonical released new kernel security updates for all supported Ubuntu Linux releases to address the recently disclosed L1 Terminal Fault (L1TF) vulnerabilities CVE-2018-3620 and CVE-2018-3646.

The kernel security update addressed both the L1 Terminal Fault vulnerabilities, as well as two other security flaws (CVE-2018-5390 and CVE-2018-5391) discovered by Juha-Matti Tilli in Linux kernel's TCP and IP implementations, which could allow remote attackers to cause a denial of service.

Unfortunately, on Ubuntu 14.04 LTS (Trusty Tahr) systems, users reported that the mitigations also introduced a regression in the Linux kernel packages, which could cause kernel panics for some users that booted the OS in certain desktop environments.

The regression also appears to have prevented Java applications from starting on Ubuntu 14.04 LTS systems so Canonical has addressed the issue and released a new kernel version, urging all users to update their installations as soon as possible.

"Unfortunately, the update introduced regressions that caused kernel panics when booting in some environments as well as preventing Java applications from starting. This update fixes the problems. We apologize for the inconvenience," reads the security advisory.

Ubuntu 14.04 LTS users must update their systems now

If you're using the Ubuntu 14.04 LTS (Trusty Tahr) operating system with the original Linux 3.13 kernel, you should update your installations right now to linux-image 3.13.0-156.206 on either 32-bit, 64-bit, or PowerPC 64-bit systems, whether you're using the generic, lowlatency, or generic-lpae kernels.

After a standard kernel update, users are recommended to reboot their machines and, if necessary, rebuild any kernel modules they might have installed if you manually uninstalled the standard kernel metapackages. Follow the instructions provided by Canonical at https://wiki.ubuntu.com/Security/Upgrades to update your PC.

Update 22/08/18: The regression has also been fixed for Ubuntu 12.04 ESM (Extended Security Maintenance) users running the HWE (Hardware Enablement) Linux kernel from Ubuntu 14.04 LTS (Trusty Tahr). Please update to linux-image-3.13.0-156-generic  3.13.0-156.206~precise1 as soon as possible!