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Ubuntu Security Notice USN-5192-2
December 17, 2021

apache-log4j2 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

Apache Log4j 2 could be made to crash or run programs as an administrator
if it received a specially crafted input.

Software Description:
- apache-log4j2: Apache Log4j - Logging Framework for Java

Details:

USN-5192-1 fixed a vulnerability in Apache Log4j 2. This update provides
the corresponding update for Ubuntu 16.04 ESM.

Original advisory details:

 Chen Zhaojun discovered that Apache Log4j 2 allows remote attackers to run
 programs via a special crafted input. An attacker could use this vulnerability
 to cause 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:
  liblog4j2-java                  2.4-2ubuntu0.1~esm1

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

References:
  https://ubuntu.com/security/notices/USN-5192-2
  https://ubuntu.com/security/notices/USN-5192-1
  CVE-2021-44228