A Linux kernel (IoT) security update has been released for Ubuntu Linux 20.04 LTS.

[USN-6261-1] Linux kernel (IoT) vulnerabilities

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Ubuntu Security Notice USN-6261-1
July 28, 2023

linux-iot vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-iot: Linux kernel for IoT platforms

Details:

It was discovered that the IP-VLAN network driver for the Linux kernel did
not properly initialize memory in some situations, leading to an out-of-
bounds write vulnerability. An attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2023-3090)

Shir Tamari and Sagi Tzadik discovered that the OverlayFS implementation in
the Ubuntu Linux kernel did not properly perform permission checks in
certain situations. A local attacker could possibly use this to gain
elevated privileges. (CVE-2023-32629)

It was discovered that the netfilter subsystem in the Linux kernel did not
properly handle some error conditions, leading to 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-2023-3390)

Tanguy Dubroca discovered that the netfilter subsystem in the Linux kernel
did not properly handle certain pointer data type, leading to an out-of-
bounds write vulnerability. A privileged attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2023-35001)

Update instructions:

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

Ubuntu 20.04 LTS:
linux-image-5.4.0-1018-iot 5.4.0-1018.19

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-6261-1
CVE-2023-3090, CVE-2023-32629, CVE-2023-3390, CVE-2023-35001

Package Information:
https://launchpad.net/ubuntu/+source/linux-iot/5.4.0-1018.19