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 These new images superseded the existing images [2].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:
 * cloud-init: 20.4-0ubuntu1~18.04.2 => 20.4.1-0ubuntu1~18.04.1 
 * dnsmasq: 2.79-1 => 2.79-1ubuntu0.2 


The following is a complete changelog for this image.
new: {}
removed: {}
changed: ['cloud-init', 'dnsmasq-base']
new snaps: {}
removed snaps: {}
changed snaps: []
==== cloud-init: 20.4-0ubuntu1~18.04.2 => 20.4.1-0ubuntu1~18.04.1 ====
====     cloud-init
  * New upstream release. (LP: #1911680)
    - Release 20.4.1
    - Revert "ssh_util: handle non-default AuthorizedKeysFile config (#586)"
==== dnsmasq: 2.79-1 => 2.79-1ubuntu0.2 ====
====     dnsmasq-base
  * SECURITY UPDATE: Multiple security issues
    - CVE-2020-25681: heap overflow in RRSets sorting
    - CVE-2020-25682: buffer overflow in extracting names from DNS packets
    - CVE-2020-25683: heap overflow in DNSSEC validation
    - CVE-2020-25684: cache poisoning issue via address/port
    - CVE-2020-25685: cache poisoning issue via weak hash
    - CVE-2020-25686: birthday attack via incorrect existing requests check
    - CVE-2020-25687: heap overflow in DNSSEC validation
    - CVE-2019-14834: memory leak via DHCP response creation

--
[1] http://cloud-images.ubuntu.com/releases/bionic/release-20210119.1/
[2] http://cloud-images.ubuntu.com/releases/bionic/release-20210118/