Ubuntu Security Notices
USN-4463-1

USN-4463-1: Linux kernel vulnerabilities

Publication date

18 August 2020

Overview

Several security issues were fixed in the Linux kernel.

Releases

16.04 LTS 14.04 LTS

Packages

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
linux-raspi2 - Linux kernel for Raspberry Pi (V7) systems
linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

It was discovered that the bcache subsystem in the Linux kernel did not
properly release a lock in some error conditions. A local attacker could
possibly use this to cause a denial of service. (CVE-2020-12771)

Kyungtae Kim discovered that the USB testing driver in the Linux kernel did
not properly deallocate memory on disconnect events. A physically proximate
attacker could use this to cause a denial of service (memory exhaustion).
(CVE-2020-15393)

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
16.04 xenial	linux-image-4.4.0-1078-kvm – 4.4.0-1078.85
	linux-image-4.4.0-1112-aws – 4.4.0-1112.124
	linux-image-4.4.0-1137-raspi2 – 4.4.0-1137.146
	linux-image-4.4.0-1141-snapdragon – 4.4.0-1141.149
	linux-image-4.4.0-187-generic – 4.4.0-187.217
	linux-image-4.4.0-187-generic-lpae – 4.4.0-187.217
	linux-image-4.4.0-187-lowlatency – 4.4.0-187.217
	linux-image-4.4.0-187-powerpc-e500mc – 4.4.0-187.217
	linux-image-4.4.0-187-powerpc-smp – 4.4.0-187.217
	linux-image-4.4.0-187-powerpc64-emb – 4.4.0-187.217
	linux-image-4.4.0-187-powerpc64-smp – 4.4.0-187.217
	linux-image-aws – 4.4.0.1112.117
	linux-image-generic – 4.4.0.187.193
	linux-image-generic-lpae – 4.4.0.187.193
	linux-image-kvm – 4.4.0.1078.76
	linux-image-lowlatency – 4.4.0.187.193
	linux-image-powerpc-e500mc – 4.4.0.187.193
	linux-image-powerpc-smp – 4.4.0.187.193
	linux-image-powerpc64-emb – 4.4.0.187.193
	linux-image-powerpc64-smp – 4.4.0.187.193
	linux-image-raspi2 – 4.4.0.1137.137
	linux-image-snapdragon – 4.4.0.1141.133
	linux-image-virtual – 4.4.0.187.193
14.04 trusty	linux-image-4.4.0-1076-aws – 4.4.0-1076.80
	linux-image-4.4.0-187-generic – 4.4.0-187.217~14.04.1
	linux-image-4.4.0-187-generic-lpae – 4.4.0-187.217~14.04.1
	linux-image-4.4.0-187-lowlatency – 4.4.0-187.217~14.04.1
	linux-image-4.4.0-187-powerpc-e500mc – 4.4.0-187.217~14.04.1
	linux-image-4.4.0-187-powerpc-smp – 4.4.0-187.217~14.04.1
	linux-image-4.4.0-187-powerpc64-emb – 4.4.0-187.217~14.04.1
	linux-image-4.4.0-187-powerpc64-smp – 4.4.0-187.217~14.04.1
	linux-image-aws – 4.4.0.1076.73
	linux-image-generic-lpae-lts-xenial – 4.4.0.187.164
	linux-image-generic-lts-xenial – 4.4.0.187.164
	linux-image-lowlatency-lts-xenial – 4.4.0.187.164
	linux-image-powerpc-e500mc-lts-xenial – 4.4.0.187.164
	linux-image-powerpc-smp-lts-xenial – 4.4.0.187.164
	linux-image-powerpc64-emb-lts-xenial – 4.4.0.187.164
	linux-image-powerpc64-smp-lts-xenial – 4.4.0.187.164
	linux-image-virtual-lts-xenial – 4.4.0.187.164

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References

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