A Linux kernel security update has been released for Ubuntu Linux 14.04 ESM and 16.04 ESM.

USN-6045-1: Linux kernel vulnerabilities

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Ubuntu Security Notice USN-6045-1
April 26, 2023

linux, linux-aws, linux-kvm, linux-lts-xenial vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-kvm: Linux kernel for cloud environments
- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

It was discovered that the Traffic-Control Index (TCINDEX) implementation
in the Linux kernel did not properly perform filter deactivation in some
situations. A local attacker could possibly use this to gain elevated
privileges. Please note that with the fix for this CVE, kernel support for
the TCINDEX classifier has been removed. (CVE-2023-1829)

Gwnaun Jung discovered that the SFB packet scheduling implementation 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-2022-3586)

Zheng Wang and Zhuorao Yang discovered that the RealTek RTL8712U wireless
driver 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-2022-4095)

It was discovered that the TIPC protocol implementation in the Linux kernel
did not properly validate the queue of socket buffers (skb) when handling
certain UDP packets. A remote attacker could use this to cause a denial of
service. (CVE-2023-1390)

It was discovered that the Xircom PCMCIA network device driver in the Linux
kernel did not properly handle device removal events. A physically
proximate attacker could use this to cause a denial of service (system
crash). (CVE-2023-1670)

Update instructions:

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

Ubuntu 16.04 ESM:
linux-image-4.4.0-1119-kvm 4.4.0-1119.129
linux-image-4.4.0-1156-aws 4.4.0-1156.171
linux-image-4.4.0-240-generic 4.4.0-240.274
linux-image-4.4.0-240-lowlatency 4.4.0-240.274
linux-image-aws 4.4.0.1156.160
linux-image-generic 4.4.0.240.246
linux-image-generic-lts-xenial 4.4.0.240.246
linux-image-kvm 4.4.0.1119.116
linux-image-lowlatency 4.4.0.240.246
linux-image-lowlatency-lts-xenial 4.4.0.240.246
linux-image-virtual 4.4.0.240.246
linux-image-virtual-lts-xenial 4.4.0.240.246

Ubuntu 14.04 ESM:
linux-image-4.4.0-1118-aws 4.4.0-1118.124
linux-image-4.4.0-240-generic 4.4.0-240.274~14.04.1
linux-image-4.4.0-240-lowlatency 4.4.0-240.274~14.04.1
linux-image-aws 4.4.0.1118.115
linux-image-generic-lts-xenial 4.4.0.240.208
linux-image-lowlatency-lts-xenial 4.4.0.240.208
linux-image-virtual-lts-xenial 4.4.0.240.208

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

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.

References:
https://ubuntu.com/security/notices/USN-6045-1
CVE-2022-3586, CVE-2022-4095, CVE-2023-1390, CVE-2023-1670,
CVE-2023-1829