Users of the Debian GNU/Linux and Ubuntu Linux distributions received important kernel security updates that address multiple vulnerabilities discovered by various security researchers.
On October 18th, 2022, Debian GNU/Linux 11 “Bullseye” users received a new major kernel update patching a total of 17 security vulnerabilities, including CVE-2022-3176 and CVE-2022-2602, two flaws discovered in the io_uring subsystem that could lead to local privilege escalation to root, and CVE-2022-40307, a race condition discovered in the EFI capsule-loader driver that could also lead to local privilege escalation or a denial of service (crash or memory corruption).
Also patched are CVE-2022-20421, another use-after-free vulnerability that could lead to privilege escalation, CVE-2022-39188, a race condition discovered by Google Project Zero’s Jann Horn in the kernel’s handling of unmapping of specific memory ranges, which could also lead to local privilege escalation or denial of service, and CVE-2022-39842, an integer overflow discovered in the pxa3xx-gcu video driver that could lead to a heap out-of-bounds write.
The new Debian Bullseye kernel security update also patches CVE-2022-41674, CVE-2022-42719, CVE-2022-42720, CVE-2022-42721, and CVE-2022-42722, several vulnerabilities discovered by Sönke Huster in the WiFi driver stack (mac80211 subsystem) triggered by WLAN frames, which may result in denial of service or code execution, as well as CVE-2022-3303, a race condition discovered in the sound subsystem, and CVE-2022-3061, a flaw discovered in the i740 driver, both of which leading to denial of service attacks.
Another interesting flaw patched in the new kernel security update for Debian GNU/Linux 11 “Bullseye” is CVE-2022-2663, which was discovered by David Leadbeater in the nf_conntrack_irc connection-tracking protocol module, which, when enabled on a firewall, could allow an external user on the same IRC network as an internal user to “exploit its lax parsing to open arbitrary TCP ports in the firewall and reveal their public IP address, or to block their IRC connection at the firewall,” reads the security advisory.
Other security flaws include CVE-2021-4037, a vulnerability reported by Christian Brauner in the XFS file system that could allow local users to create files with unintended group ownership, allowing attackers to escalate privileges by making a plain file executable and SGID, as well as CVE-2022-0171, a cache incoherence issue discovered by Mingwei Zhang in the KVM subsystem that could lead to a denial of service, and CVE-2022-1184, a flaw discovered in the EXT4 file system driver that could lead to a use-after-free and allow a privileged local user to cause a denial of service (crash or memory corruption) or escalate his/her privileges.
On the other hand, Ubuntu users received new kernel security updates for Ubuntu 22.04 LTS and Ubuntu 20.04 LTS systems running Linux kernel 5.15 LTS, as well as Ubuntu 20.04 LTS and Ubuntu 18.04 LTS systems running Linux kernel 5.4 LTS, patching all the WiFi driver stack vulnerabilities mentioned above and the privilege escalation flaw discovered by David Bouman and Billy Jheng Bing Jhong in the io_uring subsystem (CVE-2022-2602).
Users of the Debian GNU/Linux 11 “Bullseye” operating system are urged to update their installations to kernel 5.10.149-1, while Ubuntu 22.04 LTS and Ubuntu 20.04.5 LTS users need to update their machines to linux-image 5.15.0-52.58 and linux-image 5.15.0-52.58~20.04.1 respectively, and Ubuntu 20.04 LTS and Ubuntu 18.04.6 LTS users to linux-image 5.4.0-131.147 and linux-image-hwe 184.108.40.206.147~18.04.108 respectively.
Performing a kernel security update on Debian or Ubuntu systems is as simple as running the
sudo apt update && sudo apt full-upgrade command in a terminal emulator. Don’t forget to reboot your installations after the new kernel packages have been successfully installed, as well as to recompile and reinstall any third-party kernel modules where necessary.
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