Canonical has released today new Linux kernel security updates for all supported Ubuntu releases to address a total of four security vulnerabilities discovered by various researchers.
Affecting all supported Ubuntu releases and kernels, a flaw (CVE-2020-8428) discovered by Al Viro in Linux kernel’s VFS (Virtual Filesystem Switch) layer, which could allow a local attacker to crash the system or expose sensitive information, was patched in this update.
On top of that, the new Linux kernel security update also fixes a vulnerability (CVE-2019-19046) discovered in the IPMI message handler implementation, which could allow a local attacker to cause a denial of service (kernel memory exhaustion). This flaw affects only Ubuntu 19.10 and Ubuntu 18.04.4 LTS systems running Linux kernel 5.3.
Two other vulnerabilities were addressed in the Linux 4.15 kernel packages of Ubuntu 18.04 LTS and Ubuntu 16.04 LTS systems. The first if a KVM flaw (CVE-2020-8834) discovered by Gustavo Romero and Paul Mackerras, which only affects PowerPC processors and lets local attackers in a KVM guest to crash the host system.
The second flaw (CVE-2020-8992) was discovered by Shijie Luo in Linux kernel’s EXT4 file system, which incorrectly checked for a too-large journal size, allowing an attacker to cause a denial of service (soft lockup) by constructing and mounting a malicious EXT4 image.
Canonical urges all Ubuntu users to update the kernel packages as soon as possible to the new versions available in the main repositories for all supported architectures.
On 64-bit systems, you have to update to linux-image 5.3.0-46.38 on Ubuntu 19.10, linux-image 5.3.0-46.38~18.04.1 on Ubuntu 18.04.4 LTS, linux-image 22.214.171.124.87 on Ubuntu 18.04 LTS, linux-image-hwe 126.96.36.199.104 on Ubuntu 16.04.6 LTS, and linux-image 4.4.0-177.207 on Ubuntu 16.04 LTS.
Please keep in mind to reboot your systems and reinstall any third-party kernel modules you might have installed after applying the new Linux kernel security updates for Ubuntu. More details can be found at https://wiki.ubuntu.com/Security/Upgrades.
Last updated 7 months ago