An Expat security update has been released for Ubuntu Linux 16.04 ESM.

USN-5638-1: Expat vulnerability

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Ubuntu Security Notice USN-5638-1
September 26, 2022

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

- Ubuntu 16.04 ESM

Summary:

Expat could be made to crash or execute arbitrary code.

Software Description:
- expat: XML parsing C library

Details:

Rhodri James discovered that Expat incorrectly handled memory when
processing certain malformed XML files. An attacker could possibly
use this issue to cause a crash or execute arbitrary code.

Update instructions:

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

Ubuntu 16.04 ESM:
expat 2.1.0-7ubuntu0.16.04.5+esm6
lib64expat1 2.1.0-7ubuntu0.16.04.5+esm6
libexpat1 2.1.0-7ubuntu0.16.04.5+esm6

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

References:
https://ubuntu.com/security/notices/USN-5638-1
CVE-2022-40674