A GnuTLS security update has been released for Ubuntu Linux 20.04 LTS.

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Ubuntu Security Notice USN-5029-1
August 02, 2021

gnutls28 vulnerabilities
==========================================================================

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

- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in GnuTLS.

Software Description:
- gnutls28: GNU TLS library

Details:

It was discovered that GnuTLS incorrectly handled sending certain
extensions when being used as a client. A remote attacker could use this
issue to cause GnuTLS 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 20.04 LTS:
libgnutls30 3.6.13-2ubuntu1.6

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

References:
  https://ubuntu.com/security/notices/USN-5029-1
CVE-2021-20231, CVE-2021-20232

Package Information:
  https://launchpad.net/ubuntu/+source/gnutls28/3.6.13-2ubuntu1.6