==========================================================================
Ubuntu Security Notice USN-4710-1
January 28, 2021

linux vulnerability
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS

Summary:

The system could be made to crash under certain conditions.

Software Description:
- linux: Linux kernel

Details:

Kiyin (尹亮) discovered that the perf subsystem in the Linux kernel did
not properly deallocate memory in some situations. A privileged attacker
could use this to cause a denial of service (kernel memory exhaustion).

Update instructions:

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

Ubuntu 18.04 LTS:
  linux-image-4.15.0-135-generic  4.15.0-135.139
  linux-image-4.15.0-135-generic-lpae  4.15.0-135.139
  linux-image-4.15.0-135-lowlatency  4.15.0-135.139
  linux-image-generic             4.15.0.135.122
  linux-image-generic-lpae        4.15.0.135.122
  linux-image-lowlatency          4.15.0.135.122
  linux-image-powerpc-e500mc      4.15.0.135.122
  linux-image-powerpc-smp         4.15.0.135.122
  linux-image-powerpc64-emb       4.15.0.135.122
  linux-image-powerpc64-smp       4.15.0.135.122
  linux-image-virtual             4.15.0.135.122

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.

References:
  https://usn.ubuntu.com/4710-1
  CVE-2020-25704

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.15.0-135.139