=========================================================================Ubuntu Security Notice USN-5325-1
March 14, 2022

zsh vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in Zsh.

Software Description:
- zsh: shell with lots of features

Details:

Sam Foxman discovered that Zsh incorrectly handled certain inputs.
An attacker could possibly use this issue to regain dropped privileges.
(CVE-2019-20044)

It was discovered that Zsh incorrectly handled certain inputs.
An attacker could possibly use this issue to execute arbitrary code.
(CVE-2021-45444)

Update instructions:

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

Ubuntu 21.10:
   zsh                             5.8-6ubuntu0.1
   zsh-static                      5.8-6ubuntu0.1

Ubuntu 20.04 LTS:
   zsh                             5.8-3ubuntu1.1
   zsh-static                      5.8-3ubuntu1.1

Ubuntu 18.04 LTS:
   zsh                             5.4.2-3ubuntu3.2
   zsh-static                      5.4.2-3ubuntu3.2

Ubuntu 16.04 ESM:
   zsh                             5.1.1-1ubuntu2.3+esm1
   zsh-static                      5.1.1-1ubuntu2.3+esm1

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

References:
   https://ubuntu.com/security/notices/USN-5325-1
   CVE-2019-20044, CVE-2021-45444

Package Information:
   https://launchpad.net/ubuntu/+source/zsh/5.8-6ubuntu0.1
   https://launchpad.net/ubuntu/+source/zsh/5.8-3ubuntu1.1
   https://launchpad.net/ubuntu/+source/zsh/5.4.2-3ubuntu3.2