USN-4876-1: Linux kernel vulnerabilities

Publication date

16 March 2021

Overview

Several security issues were fixed in the Linux kernel.


Packages

Details

Olivier Benjamin and Pawel Wieczorkiewicz discovered a race condition the
Xen paravirt block backend in the Linux kernel, leading to a use-after-free
vulnerability. An attacker in a guest VM could use this to cause a denial
of service in the host OS. (CVE-2020-29569)

It was discovered that the Marvell WiFi-Ex device driver in the Linux
kernel did not properly validate ad-hoc SSIDs. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2020-36158)

吴异 discovered that the NFS implementation in the Linux kernel did not
properly prevent access outside of an NFS export that is a subdirectory of
a file system. An attacker could possibly use this to bypass NFS access
restrictions. (CVE-2021-3178)

Olivier Benjamin and Pawel Wieczorkiewicz discovered a race condition the
Xen paravirt block backend in the Linux kernel, leading to a use-after-free
vulnerability. An attacker in a guest VM could use this to cause a denial
of service in the host OS. (CVE-2020-29569)

It was discovered that the Marvell WiFi-Ex device driver in the Linux
kernel did not properly validate ad-hoc SSIDs. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2020-36158)

吴异 discovered that the NFS implementation in the Linux kernel did not
properly prevent access outside of an NFS export that is a subdirectory of
a file system. An attacker could possibly use this to bypass NFS access
restrictions. (CVE-2021-3178)

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-4.4.0-1089-kvm –  4.4.0-1089.98
linux-image-4.4.0-1123-aws –  4.4.0-1123.137
linux-image-4.4.0-1147-raspi2 –  4.4.0-1147.157
linux-image-4.4.0-1151-snapdragon –  4.4.0-1151.161
linux-image-4.4.0-204-generic –  4.4.0-204.236
linux-image-4.4.0-204-generic-lpae –  4.4.0-204.236
linux-image-4.4.0-204-lowlatency –  4.4.0-204.236
linux-image-4.4.0-204-powerpc-e500mc –  4.4.0-204.236
linux-image-4.4.0-204-powerpc-smp –  4.4.0-204.236
linux-image-4.4.0-204-powerpc64-emb –  4.4.0-204.236
linux-image-4.4.0-204-powerpc64-smp –  4.4.0-204.236
linux-image-aws –  4.4.0.1123.128
linux-image-generic –  4.4.0.204.210
linux-image-generic-lpae –  4.4.0.204.210
linux-image-kvm –  4.4.0.1089.87
linux-image-lowlatency –  4.4.0.204.210
linux-image-powerpc-e500mc –  4.4.0.204.210
linux-image-powerpc-smp –  4.4.0.204.210
linux-image-powerpc64-emb –  4.4.0.204.210
linux-image-powerpc64-smp –  4.4.0.204.210
linux-image-raspi2 –  4.4.0.1147.147
linux-image-snapdragon –  4.4.0.1151.143
linux-image-virtual –  4.4.0.204.210
14.04 trusty linux-image-4.4.0-1087-aws –  4.4.0-1087.91
linux-image-4.4.0-204-generic –  4.4.0-204.236~14.04.1
linux-image-4.4.0-204-generic-lpae –  4.4.0-204.236~14.04.1
linux-image-4.4.0-204-lowlatency –  4.4.0-204.236~14.04.1
linux-image-4.4.0-204-powerpc-e500mc –  4.4.0-204.236~14.04.1
linux-image-4.4.0-204-powerpc-smp –  4.4.0-204.236~14.04.1
linux-image-4.4.0-204-powerpc64-emb –  4.4.0-204.236~14.04.1
linux-image-4.4.0-204-powerpc64-smp –  4.4.0-204.236~14.04.1
linux-image-aws –  4.4.0.1087.84
linux-image-generic-lpae-lts-xenial –  4.4.0.204.178
linux-image-generic-lts-xenial –  4.4.0.204.178
linux-image-lowlatency-lts-xenial –  4.4.0.204.178
linux-image-powerpc-e500mc-lts-xenial –  4.4.0.204.178
linux-image-powerpc-smp-lts-xenial –  4.4.0.204.178
linux-image-powerpc64-emb-lts-xenial –  4.4.0.204.178
linux-image-powerpc64-smp-lts-xenial –  4.4.0.204.178
linux-image-virtual-lts-xenial –  4.4.0.204.178

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