=========================================================================
Ubuntu Security Notice USN-4967-2
May 27, 2021

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

- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

nginx could be made to crash or run programs if it received specially
crafted network traffic.

Software Description:
- nginx: small, powerful, scalable web/proxy server

Details:

USN-4967-1 fixed a vulnerability in nginx. This update provides
the corresponding update for Ubuntu 14.04 ESM and 16.04 ESM.

Original advisory details:

 Luis Merino, Markus Vervier, and Eric Sesterhenn discovered that nginx
 incorrectly handled responses to the DNS resolver. A remote attacker could
 use this issue to cause nginx to crash, resulting in a denial of service,
 or possibly execute arbitrary code.

Update instructions:

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

Ubuntu 16.04 ESM:
  nginx                           1.10.3-0ubuntu0.16.04.5+esm1
  nginx-common                    1.10.3-0ubuntu0.16.04.5+esm1
  nginx-core                      1.10.3-0ubuntu0.16.04.5+esm1
  nginx-extras                    1.10.3-0ubuntu0.16.04.5+esm1
  nginx-full                      1.10.3-0ubuntu0.16.04.5+esm1
  nginx-light                     1.10.3-0ubuntu0.16.04.5+esm1

Ubuntu 14.04 ESM:
  nginx                           1.4.6-1ubuntu3.9+esm2
  nginx-common                    1.4.6-1ubuntu3.9+esm2
  nginx-core                      1.4.6-1ubuntu3.9+esm2
  nginx-extras                    1.4.6-1ubuntu3.9+esm2
  nginx-full                      1.4.6-1ubuntu3.9+esm2
  nginx-light                     1.4.6-1ubuntu3.9+esm2

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-4967-2
  https://ubuntu.com/security/notices/USN-4967-1
  CVE-2021-23017