Ubuntu Security Notices
USN-5000-1

USN-5000-1: Linux kernel vulnerabilities

Publication date

23 June 2021

Overview

Several security issues were fixed in the Linux kernel.

Releases

20.04 LTS 18.04 LTS

Packages

linux - Linux kernel
linux-aws - Linux kernel for Amazon Web Services (AWS) systems
linux-aws-5.4 - Linux kernel for Amazon Web Services (AWS) systems
linux-azure - Linux kernel for Microsoft Azure Cloud systems
linux-azure-5.4 - Linux kernel for Microsoft Azure cloud systems
linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
linux-gcp-5.4 - Linux kernel for Google Cloud Platform (GCP) systems
linux-gke - Linux kernel for Google Container Engine (GKE) systems
linux-gke-5.4 - Linux kernel for Google Container Engine (GKE) systems
linux-gkeop - Linux kernel for Google Container Engine (GKE) systems
linux-gkeop-5.4 - Linux kernel for Google Container Engine (GKE) systems
linux-hwe-5.4 - Linux hardware enablement (HWE) kernel
linux-oracle - Linux kernel for Oracle Cloud systems
linux-oracle-5.4 - Linux kernel for Oracle Cloud systems
linux-raspi - Linux kernel for Raspberry Pi (V8) systems
linux-raspi-5.4 - Linux kernel for Raspberry Pi (V8) systems

Details

Norbert Slusarek discovered a race condition in the CAN BCM networking
protocol of the Linux kernel leading to multiple use-after-free
vulnerabilities. A local attacker could use this issue to execute arbitrary
code. (CVE-2021-3609)

Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly enforce limits for pointer operations. A local attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2021-33200)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation did
not properly clear received fragments from memory in some situations. A
physically proximate attacker could possibly use this issue to inject
packets or expose sensitive information. (CVE-2020-24586)

Mathy Vanhoef discovered that the Linux kernel’s WiFi...

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
incorrectly handled encrypted fragments. A physically proximate attacker
could possibly use this issue to decrypt fragments. (CVE-2020-24587)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
incorrectly handled certain malformed frames. If a user were tricked into
connecting to a malicious server, a physically proximate attacker could use
this issue to inject packets. (CVE-2020-24588)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
incorrectly handled EAPOL frames from unauthenticated senders. A physically
proximate attacker could inject malicious packets to cause a denial of
service (system crash). (CVE-2020-26139)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation did
not properly verify certain fragmented frames. A physically proximate
attacker could possibly use this issue to inject or decrypt packets.
(CVE-2020-26141)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
accepted plaintext fragments in certain situations. A physically proximate
attacker could use this issue to inject packets. (CVE-2020-26145)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation could
reassemble mixed encrypted and plaintext fragments. A physically proximate
attacker could possibly use this issue to inject packets or exfiltrate
selected fragments. (CVE-2020-26147)

Or Cohen discovered that the SCTP implementation in the Linux kernel
contained a race condition in some situations, leading to a use-after-free
condition. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2021-23133)

Or Cohen and Nadav Markus discovered a use-after-free vulnerability in the
nfc implementation in the Linux kernel. A privileged local attacker could
use this issue to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2021-23134)

Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly prevent speculative loads in certain situations. A local
attacker could use this to expose sensitive information (kernel memory).
(CVE-2021-31829)

It was discovered that a race condition in the kernel Bluetooth subsystem
could lead to use-after-free of slab objects. An attacker could use this
issue to possibly execute arbitrary code. (CVE-2021-32399)

It was discovered that a use-after-free existed in the Bluetooth HCI driver
of the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2021-33034)

It was discovered that an out-of-bounds (OOB) memory access flaw existed in
the f2fs module of the Linux kernel. A local attacker could use this issue
to cause a denial of service (system crash). (CVE-2021-3506)

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
20.04 focal	linux-image-gkeop-5.4 – 5.4.0.1018.21
	linux-image-5.4.0-1038-raspi – 5.4.0-1038.41
	linux-image-5.4.0-1051-aws – 5.4.0-1051.53
	linux-image-gke – 5.4.0.1046.55
	linux-image-5.4.0-1048-oracle – 5.4.0-1048.52
	linux-image-oem-osp1 – 5.4.0.77.80
	linux-image-5.4.0-1018-gkeop – 5.4.0-1018.19
	linux-image-5.4.0-1046-gke – 5.4.0-1046.48
	linux-image-oracle-lts-20.04 – 5.4.0.1048.48
	linux-image-gkeop – 5.4.0.1018.21
	linux-image-virtual – 5.4.0.77.80
	linux-image-raspi – 5.4.0.1038.73
	linux-image-gcp-lts-20.04 – 5.4.0.1046.55
	linux-image-5.4.0-1051-azure – 5.4.0-1051.53
	linux-image-generic – 5.4.0.77.80
	linux-image-aws-lts-20.04 – 5.4.0.1051.53
	linux-image-gke-5.4 – 5.4.0.1046.55
	linux-image-oem – 5.4.0.77.80
	linux-image-raspi2 – 5.4.0.1038.73
	linux-image-azure-lts-20.04 – 5.4.0.1051.49
	linux-image-generic-lpae – 5.4.0.77.80
	linux-image-5.4.0-77-lowlatency – 5.4.0-77.86
	linux-image-5.4.0-77-generic – 5.4.0-77.86
	linux-image-5.4.0-1046-gcp – 5.4.0-1046.49
	linux-image-lowlatency – 5.4.0.77.80
	linux-image-5.4.0-77-generic-lpae – 5.4.0-77.86
18.04 bionic	linux-image-gkeop-5.4 – 5.4.0.1018.19~18.04.19
	linux-image-5.4.0-1038-raspi – 5.4.0-1038.41~18.04.1
	linux-image-5.4.0-1051-aws – 5.4.0-1051.53~18.04.1
	linux-image-5.4.0-1048-oracle – 5.4.0-1048.52~18.04.1
	linux-image-oem-osp1 – 5.4.0.77.86~18.04.69
	linux-image-oracle – 5.4.0.1048.52~18.04.30
	linux-image-generic-hwe-18.04 – 5.4.0.77.86~18.04.69
	linux-image-azure – 5.4.0.1051.30
	linux-image-5.4.0-1018-gkeop – 5.4.0-1018.19~18.04.1
	linux-image-5.4.0-1046-gke – 5.4.0-1046.48~18.04.1
	linux-image-generic-lpae-hwe-18.04 – 5.4.0.77.86~18.04.69
	linux-image-snapdragon-hwe-18.04 – 5.4.0.77.86~18.04.69
	linux-image-5.4.0-1051-azure – 5.4.0-1051.53~18.04.1
	linux-image-lowlatency-hwe-18.04 – 5.4.0.77.86~18.04.69
	linux-image-virtual-hwe-18.04 – 5.4.0.77.86~18.04.69
	linux-image-gke-5.4 – 5.4.0.1046.48~18.04.12
	linux-image-oem – 5.4.0.77.86~18.04.69
	linux-image-aws – 5.4.0.1051.33
	linux-image-raspi-hwe-18.04 – 5.4.0.1038.40
	linux-image-gcp – 5.4.0.1046.33
	linux-image-5.4.0-77-lowlatency – 5.4.0-77.86~18.04.1
	linux-image-5.4.0-77-generic – 5.4.0-77.86~18.04.1
	linux-image-5.4.0-1046-gcp – 5.4.0-1046.49~18.04.1
	linux-image-5.4.0-77-generic-lpae – 5.4.0-77.86~18.04.1

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References

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