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Linux Kernel Vulnerabilities — Ubuntu Security Update (USN-8968-1)

USN-8968-1 updates Ubuntu kernels fixing CVE-2021-3640 — a Bluetooth subsystem use-after-free allowing a local attacker to crash the system or possibly execute arbitrary code — and CVE-2022-49058. Update and reboot: sudo apt update && sudo apt upgrade, then restart into the new kernel.

High 7 CVSS 2026-11-03

Ubuntu 20.04 Ubuntu 22.04

Что это значит по лицензии SharedLicense

A Bluetooth use-after-free is reachable by any nearby attacker pairing or connecting over BT — on servers it is mostly a local surface, on laptops and workstations with Bluetooth radios it is remote-adjacent.

Ubuntu Security Notices
USN-8968-1

Publication date

3 November 2026

Overview

Several security issues were fixed in the Linux kernel.

Releases

14.04 LTS

Packages

linux – Linux kernel

Details

It was discovered that the Bluetooth subsystem in the Linux kernel
contained a use-after-free vulnerability. A local attacker could use this
to cause a denial of service (system crash) or possibly execute arbitrary
code. (CVE-2021-3640)

Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:

File systems infrastructure

Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:

File systems infrastructure

Update instructions

After a standard system update you need to reboot your computer to make
all the necessary changes.

Learn more about how to get the fixes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release	Package Version
14.04 LTS trusty	linux-image-3.13.0-219-generic – 3.13.0-219.270 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.
	linux-image-3.13.0-219-lowlatency – 3.13.0-219.270 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.
	linux-image-generic – 3.13.0.219.229 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.
	linux-image-generic-lts-trusty – 3.13.0.219.229 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.
	linux-image-lowlatency – 3.13.0.219.229 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.
	linux-image-server – 3.13.0.219.229 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.
	linux-image-virtual – 3.13.0.219.229 Ubuntu Pro Fix available with Ubuntu Pro via Legacy Support add-on.

References

Related notices

Have additional questions?

Talk to a member of the team ›

Часто задаваемые вопросы

What is CVE-2021-3640?

It is a use-after-free in the Linux kernel's Bluetooth subsystem reachable through crafted Bluetooth operations — a local attacker can crash the system or possibly execute arbitrary code. Fixed with CVE-2022-49058 in the USN-8968-1 kernel update.

Do servers need this update?

Only if Bluetooth is enabled — most servers have no BT radio. Workstations and laptops do, and there the update prevents a local privilege-escalation path.

How do I apply the fix?

Run sudo apt update && sudo apt upgrade and reboot into the new kernel; verify with uname -r. If Bluetooth is unused, disabling the bluetooth service removes the surface entirely.

Why is an old CVE arriving now?

Ubuntu backports kernel fixes to its LTS kernel branches in batches — CVE-2021-3640 reached the flavor kernels in this wave. The CVE year reflects discovery, not patch priority.

Источники

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