Ubuntu Security Notices
USN-5092-1

USN-5092-1: Linux kernel vulnerabilities

Publication date

28 September 2021

Overview

Several security issues were fixed in the Linux kernel.

Releases

21.04 20.04 LTS

Packages

linux - Linux kernel
linux-aws - Linux kernel for Amazon Web Services (AWS) systems
linux-aws-5.11 - Linux kernel for Amazon Web Services (AWS) systems
linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
linux-kvm - Linux kernel for cloud environments
linux-oracle - Linux kernel for Oracle Cloud systems
linux-raspi - Linux kernel for Raspberry Pi systems

Details

Valentina Palmiotti discovered that the io_uring subsystem in the Linux
kernel could be coerced to free adjacent memory. A local attacker could use
this to execute arbitrary code. (CVE-2021-41073)

Ofek Kirzner, Adam Morrison, Benedict Schlueter, and Piotr Krysiuk
discovered that the BPF verifier in the Linux kernel missed possible
mispredicted branches due to type confusion, allowing a side-channel
attack. An attacker could use this to expose sensitive information.
(CVE-2021-33624)

Benedict Schlueter discovered that the BPF subsystem in the Linux kernel
did not properly protect against Speculative Store Bypass (SSB) side-
channel attacks in some situations. A local attacker could possibly use
this to expose sensitive information. (CVE-2021-34556)

Piotr Krysiuk discovered that the BPF subsystem in the Linux...

Valentina Palmiotti discovered that the io_uring subsystem in the Linux
kernel could be coerced to free adjacent memory. A local attacker could use
this to execute arbitrary code. (CVE-2021-41073)

Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not
properly protect against Speculative Store Bypass (SSB) side-channel
attacks in some situations. A local attacker could possibly use this to
expose sensitive information. (CVE-2021-35477)

It was discovered that the tracing subsystem in the Linux kernel did not
properly keep track of per-cpu ring buffer state. A privileged attacker
could use this to cause a denial of service. (CVE-2021-3679)

It was discovered that the Option USB High Speed Mobile device driver in
the Linux kernel did not properly handle error conditions. A physically
proximate attacker could use this to cause a denial of service (system
crash) or possibly execute arbitrary code. (CVE-2021-37159)

Alexey Kardashevskiy discovered that the KVM implementation for PowerPC
systems in the Linux kernel did not properly validate RTAS arguments in
some situations. An attacker in a guest vm could use this to cause a denial
of service (host OS crash) or possibly execute arbitrary code.
(CVE-2021-37576)

It was discovered that the Virtio console implementation in the Linux
kernel did not properly validate input lengths in some situations. A local
attacker could possibly use this to cause a denial of service (system
crash). (CVE-2021-38160)

Michael Wakabayashi discovered that the NFSv4 client implementation in the
Linux kernel did not properly order connection setup operations. An
attacker controlling a remote NFS server could use this to cause a denial
of service on the client. (CVE-2021-38199)

It was discovered that the Sun RPC implementation in the Linux kernel
contained an out-of-bounds access error. A remote attacker could possibly
use this to cause a denial of service (system crash). (CVE-2021-38201)

It was discovered that the MAX-3421 host USB 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-2021-38204)

It was discovered that the Xilinx 10/100 Ethernet Lite device driver in the
Linux kernel could report pointer addresses in some situations. An attacker
could use this information to ease the exploitation of another
vulnerability. (CVE-2021-38205)

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
21.04 hirsute	linux-image-virtual – 5.11.0.37.39
	linux-image-generic – 5.11.0.37.39
	linux-image-aws – 5.11.0.1019.20
	linux-image-5.11.0-1020-gcp – 5.11.0-1020.22
	linux-image-5.11.0-1019-aws – 5.11.0-1019.20
	linux-image-5.11.0-37-generic – 5.11.0-37.41
	linux-image-5.11.0-37-generic-lpae – 5.11.0-37.41
	linux-image-raspi-nolpae – 5.11.0.1019.17
	linux-image-oem-20.04 – 5.11.0.37.39
	linux-image-gke – 5.11.0.1020.20
	linux-image-5.11.0-1019-raspi-nolpae – 5.11.0-1019.20
	linux-image-gcp – 5.11.0.1020.20
	linux-image-5.11.0-1019-raspi – 5.11.0-1019.20
	linux-image-5.11.0-37-generic-64k – 5.11.0-37.41
	linux-image-5.11.0-37-lowlatency – 5.11.0-37.41
	linux-image-oracle – 5.11.0.1019.20
	linux-image-raspi – 5.11.0.1019.17
	linux-image-5.11.0-1017-kvm – 5.11.0-1017.18
	linux-image-5.11.0-1019-oracle – 5.11.0-1019.20
	linux-image-kvm – 5.11.0.1017.18
	linux-image-generic-lpae – 5.11.0.37.39
	linux-image-generic-64k – 5.11.0.37.39
	linux-image-lowlatency – 5.11.0.37.39
20.04 focal	linux-image-5.11.0-1019-aws – 5.11.0-1019.20~20.04.1
20.04 focal	linux-image-aws – 5.11.0.1019.20~20.04.18

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References

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