A new release of the Ubuntu Cloud Images for stable Ubuntu release 16.04 LTS (Xenial Xerus) 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 These new images superseded the existing images [2].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:
 * curl: 7.47.0-1ubuntu2.18 => 7.47.0-1ubuntu2.19 
 * linux-meta: 4.4.0.206.212 => 4.4.0.208.214 
 * linux-signed: 4.4.0-206.238 => 4.4.0-208.240 


The following is a complete changelog for this image.
new: {'linux-headers-4.4.0-208': '4.4.0-208.240', 'linux-headers-4.4.0-208-generic': '4.4.0-208.240', 'linux-modules-4.4.0-208-generic': '4.4.0-208.240'}
removed: {'linux-headers-4.4.0-206-generic': '4.4.0-206.238', 'linux-headers-4.4.0-206': '4.4.0-206.238', 'linux-modules-4.4.0-206-generic': '4.4.0-206.238'}
changed: ['curl', 'libcurl3-gnutls:amd64', 'linux-headers-generic', 'linux-headers-virtual', 'linux-image-4.4.0-208-generic', 'linux-image-virtual', 'linux-virtual']
new snaps: {}
removed snaps: {}
changed snaps: []
==== curl: 7.47.0-1ubuntu2.18 => 7.47.0-1ubuntu2.19 ====
====     curl libcurl3-gnutls:amd64
  * SECURITY UPDATE: data leak via referer header field
    - debian/patches/urlapi.patch: backport url api support in
      include/curl/Makefile.am, include/curl/curl.h, include/curl/urlapi.h,
      lib/Makefile.inc, lib/urlapi-int.h, lib/urlapi.c,
      lib/curl_setup_once.h, lib/url.c, lib/url.h, lib/escape.c,
      lib/escape.h, docs/libcurl/symbols-in-versions.
    - debian/libcurl*.symbols: added new symbols.
    - debian/patches/CVE-2021-22876.patch: strip credentials from the
      auto-referer header field in lib/transfer.c.
    - CVE-2021-22876
==== linux-meta: 4.4.0.206.212 => 4.4.0.208.214 ====
====     linux-headers-generic linux-headers-virtual linux-image-virtual linux-virtual
  * Bump ABI 4.4.0-208
  * Bump ABI 4.4.0-207
==== linux-signed: 4.4.0-206.238 => 4.4.0-208.240 ====
====     linux-image-4.4.0-208-generic
  * Master version: 4.4.0-208.240
  * Master version: 4.4.0-207.239

--
[1] http://cloud-images.ubuntu.com/releases/xenial/release-20210413/
[2] http://cloud-images.ubuntu.com/releases/xenial/release-20210329.1/