Ubuntu 16.04 LTS USN-4748-1 Critical: Kernel Denial Of Service Threats

ubuntu

February 25, 2021

Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux: Linux kernel

- linux-aws: Linux kernel for Amazon Web Services (AWS) systems

- linux-kvm: Linux kernel for cloud environments

- linux-raspi2: Linux kernel for Raspberry Pi (V8) systems

- linux-snapdragon: Linux kernel for Qualcomm Snapdragon processors- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

It was discovered that the jfs file system implementation in the Linux

kernel contained an out-of-bounds read vulnerability. A local attacker

could use this to possibly cause a denial of service (system crash).

(CVE-2020-27815)

It was discovered that the memory management subsystem in the Linux kernel

did not properly handle copy-on-write operations in some situations. A

local attacker could possibly use this to gain unintended write access to

read-only memory pages. (CVE-2020-29374)

Michael Kurth and Pawel Wieczorkiewicz discovered that the Xen event

processin...

Read the Full Advisory

Topics Covered

security advisory denial of service security update kernel patch Ubuntu critical threat kernel system crash linux kernel ubuntu 16.04 cloud environments

Update Instructions

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

Ubuntu 16.04 LTS:
  linux-image-4.4.0-1088-kvm      4.4.0-1088.97
  linux-image-4.4.0-1122-aws      4.4.0-1122.136
  linux-image-4.4.0-1146-raspi2   4.4.0-1146.156
  linux-image-4.4.0-1150-snapdragon  4.4.0-1150.160
  linux-image-4.4.0-203-generic   4.4.0-203.235
  linux-image-4.4.0-203-generic-lpae  4.4.0-203.235
  linux-image-4.4.0-203-lowlatency  4.4.0-203.235
  linux-image-4.4.0-203-powerpc-e500mc  4.4.0-203.235
  linux-image-4.4.0-203-powerpc-smp  4.4.0-203.235
  linux-image-4.4.0-203-powerpc64-emb  4.4.0-203.235
  linux-image-4.4.0-203-powerpc64-smp  4.4.0-203.235
  linux-image-aws                 4.4.0.1122.127
  linux-image-generic             4.4.0.203.209
  linux-image-generic-lpae        4.4.0.203.209
  linux-image-kvm                 4.4.0.1088.86
  linux-image-lowlatency          4.4.0.203.209
  linux-image-powerpc-e500mc      4.4.0.203.209
  linux-image-powerpc-smp         4.4.0.203.209
  linux-image-powerpc64-emb       4.4.0.203.209
  linux-image-powerpc64-smp       4.4.0.203.209
  linux-image-raspi2              4.4.0.1146.146
  linux-image-snapdragon          4.4.0.1150.142
  linux-image-virtual             4.4.0.203.209

Ubuntu 14.04 ESM:
  linux-image-4.4.0-1086-aws      4.4.0-1086.90
  linux-image-4.4.0-203-generic   4.4.0-203.235~14.04.1
  linux-image-4.4.0-203-generic-lpae  4.4.0-203.235~14.04.1
  linux-image-4.4.0-203-lowlatency  4.4.0-203.235~14.04.1
  linux-image-4.4.0-203-powerpc-e500mc  4.4.0-203.235~14.04.1
  linux-image-4.4.0-203-powerpc-smp  4.4.0-203.235~14.04.1
  linux-image-4.4.0-203-powerpc64-emb  4.4.0-203.235~14.04.1
  linux-image-4.4.0-203-powerpc64-smp  4.4.0-203.235~14.04.1
  linux-image-aws                 4.4.0.1086.83
  linux-image-generic-lpae-lts-xenial  4.4.0.203.177
  linux-image-generic-lts-xenial  4.4.0.203.177
  linux-image-lowlatency-lts-xenial  4.4.0.203.177
  linux-image-powerpc-e500mc-lts-xenial  4.4.0.203.177
  linux-image-powerpc-smp-lts-xenial  4.4.0.203.177
  linux-image-powerpc64-emb-lts-xenial  4.4.0.203.177
  linux-image-powerpc64-smp-lts-xenial  4.4.0.203.177
  linux-image-virtual-lts-xenial  4.4.0.203.177

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.