Ubuntu Users Receive a New Major Linux Kernel Update, 22 Security Flaws Patched

Ubuntu Major Kernel

Canonical today released new major Linux kernel updates for all supported Ubuntu releases, including Ubuntu 21.10, 20.04 LTS, and 18.04 LTS, to address up to 22 security vulnerabilities in supported kernels.

The biggest threat patched in this new Linux kernel security update for Ubuntu systems is CVE-2022-0435, a stack-based buffer overflow vulnerability discovered by Samuel Page in Linux kernel’s TIPC (Transparent Inter-Process Communication) protocol implementation, which could allow a remote attacker to cause a denial of service (system crash) on installations that have a TIPC bearer configured. This security issue affected all supported Ubuntu systems and kernels.

Another important vulnerability patched in this new kernel security update is CVE-2022-0742, a flaw discovered in Linux kernel’s ICMPv6 implementation, which could allow a remote attacker to cause a denial of service (memory exhaustion). However, this vulnerability only affected Ubuntu 21.10 and Ubuntu 20.04 LTS systems running the Linux 5.13 kernel.

The new Ubuntu kernel security update fixes several other issues affecting all supported Ubuntu releases. These include CVE-2021-28711, CVE-2021-28712, CVE-2021-28713, CVE-2021-28714, and CVE-2021-28715, five flaws discovered by Jürgen Groß in the Xen subsystem and Xen network backend driver that could allow an attacker in a guest virtual machine to cause a denial of service (excessive kernel memory consumption) in the network
backend domain or in another guest VM.

Also affecting all supported Ubuntu releases are CVE-2022-0492, a flaw discovered by Yiqi Sun and Kevin Wang in the cgroups implementation that could allow a local attacker to gain administrative privileges, CVE-2021-4135, a security issue discovered in the simulated networking device driver that could allow a local attacker to expose sensitive information (kernel memory), and CVE-2022-0516, a flaw discovered in the KVM implementation that could allow a local attacker to obtain unauthorized memory write access.

The same goes for CVE-2021-44733, a race condition leading to a use-after-free vulnerability discovered in the ARM Trusted Execution Environment (TEE) subsystem, CVE-2021-45095, a flaw discovered in the Phone Network protocol (PhoNet) implementation, and CVE-2021-45480, a security issue discovered in the Reliable Datagram Sockets (RDS) protocol implementation. All these flaws could allow local attackers to cause a denial of service or possibly execute arbitrary code.

Also patched are several flaws affecting only Ubuntu 21.10 and 20.04 LTS systems running Linux kernel 5.13, such as CVE-2022-23222, a security issue discovered in the BPF verifier, CVE-2021-39685, an out of bounds reads or write flaw discovered by Szymon Heidrich in the USB Gadget subsystem, CVE-2021-39698, a race condition discovered in the poll implementation, as well as CVE-2021-43975, a security issue discovered by Brendan Dolan-Gavitt in the aQuantia AQtion Ethernet device driver. These vulnerabilities could allow local attackers to cause a denial of service (system crash) or execute arbitrary code.

The same goes for CVE-2021-4197, a flaw discovered by Eric Biederman in the cgroup process migration implementation that could allow a local attacker to gain administrative privileges, CVE-2021-45402 and CVE-2022-0264, vulnerabilities found in the eBPF verifier and the BPF subsystem that could allow a local attacker to expose sensitive information (kernel pointer addresses), and CVE-2022-0382, another flaw discovered in the TIPC protocol implementation, which could allow a local attacker to expose sensitive information (kernel memory).

Last but not least, the new Ubuntu kernel update fixes CVE-2021-43976, a security issue that only affects Ubuntu 20.04 LTS and Ubuntu 18.04 LTS systems running Linux kernel 5.4 LTS, discovered by Brendan Dolan-Gavitt in the Marvell WiFi-Ex USB device driver. This flaw could allow a physically proximate attacker to crash the system by causing a denial of service (DoS attack).

Canonical urges all Ubuntu users to update their installations as soon as possible to the new kernel versions (linux-image-generic 5.13.0-37.42 for Ubuntu 21.10, linux-image-generic 5.13.0-37.42~20.04.1 for Ubuntu 20.04 LTS systems running Linux kernel 5.13 HWE, linux-image-generic 5.4.0.105.119 for Ubuntu 20.04 LTS systems running Linux kernel 5.4 LTS, as well as linux-image-generic-hwe-18.04 5.4.0.105.119~18.04.90 for Ubuntu 18.04 LTS systems running Linux kernel 5.4 LTS) available in the stable repositories.

To update your installations, run the sudo apt update && sudo apt full-upgrade command in the Terminal app or install all the available updates from the Software Updater utility. Please ensure that you reboot your installations after installing the new kernel versions, as well as to rebuild and reinstall any third-party kernel modules you might have installed.

Last updated 7 months ago