A new release of the Ubuntu Cloud Images for stable Ubuntu release 18.04 LTS (Bionic Beaver) is available at [1]. These new images superseded the existing images [2]. Images are available for download or immediate use on EC2 via publish AMI ids. Users who wish to update their existing installations can do so with:
   'sudo apt-get update && sudo apt-get dist-upgrade && sudo reboot'.

The following packages have been updated. Please see the full changelogs
for a complete listing of changes:
 * ca-certificates: 20210119~18.04.1 => 20210119~18.04.2 
 * linux-meta: 4.15.0.158.147 => 4.15.0.159.148 
 * linux-signed: 4.15.0-158.166 => 4.15.0-159.167 
 * vim: 2:8.0.1453-1ubuntu1.4 => 2:8.0.1453-1ubuntu1.6 


The following is a complete changelog for this image.
new: {'linux-modules-4.15.0-159-generic': '4.15.0-159.167', 'linux-headers-4.15.0-159-generic': '4.15.0-159.167', 'linux-headers-4.15.0-159': '4.15.0-159.167'}
removed: {'linux-modules-4.15.0-158-generic': '4.15.0-158.166', 'linux-headers-4.15.0-158-generic': '4.15.0-158.166', 'linux-headers-4.15.0-158': '4.15.0-158.166'}
changed: ['ca-certificates', 'linux-headers-generic', 'linux-headers-virtual', 'linux-image-4.15.0-159-generic', 'linux-image-virtual', 'linux-virtual', 'vim', 'vim-common', 'vim-runtime', 'vim-tiny', 'xxd']
new snaps: {}
removed snaps: {}
changed snaps: []
==== ca-certificates: 20210119~18.04.1 => 20210119~18.04.2 ====
====     ca-certificates
  [ Dimitri John Ledkov ]
  * mozilla/blacklist.txt: blacklist expired "DST Root CA X3".
    (LP: #1944481)
==== linux-meta: 4.15.0.158.147 => 4.15.0.159.148 ====
====     linux-headers-generic linux-headers-virtual linux-image-virtual linux-virtual
  * Bump ABI 4.15.0-159
  * Packaging resync (LP: #1786013)
    - [Packaging] resync debian/dkms-versions from main package
==== linux-signed: 4.15.0-158.166 => 4.15.0-159.167 ====
====     linux-image-4.15.0-159-generic
  * Master version: 4.15.0-159.167
==== vim: 2:8.0.1453-1ubuntu1.4 => 2:8.0.1453-1ubuntu1.6 ====
====     vim vim-common vim-runtime vim-tiny xxd
  * SECURITY UPDATE: Fix heap-based buffer overflow when reading beyond end of
    line with invalid utf-8 character
    - debian/patches/CVE-2021-3778.patch: Validate encoding of character before
      advancing line in regexp_nfa.c.
    - CVE-2021-3778
  * SECURITY UPDATE: Fix use after free when replacing
    - debian/patches/CVE-2021-3796.patch: Get the line pointer after calling
      ins_copychar() in src/normal.c.
    - CVE-2021-3796

--
[1] http://cloud-images.ubuntu.com/releases/bionic/release-20210928/
[2] http://cloud-images.ubuntu.com/releases/bionic/release-20210922/