A GnuTLS security update has been released for Ubuntu Linux 16.04 ESM.

USN-5750-1: GnuTLS vulnerability

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Ubuntu Security Notice USN-5750-1
November 30, 2022

gnutls28 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

GnuTLS could be made to crash if it received specially crafted network
traffic from an authenticated client.

Software Description:
- gnutls28: GNU TLS library

Details:

It was discovered that GnuTLS incorrectly handled certain memory
operations. A remote attacker could possibly use this issue to cause GnuTLS
to crash, resulting in a denial of service.

Update instructions:

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

Ubuntu 16.04 ESM:
libgnutls30 3.4.10-4ubuntu1.9+esm1

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

References:
  https://ubuntu.com/security/notices/USN-5750-1
CVE-2021-4209