A Python security update has been released for Ubuntu Linux 20.04 LTS and 20.10.

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Ubuntu Security Notice USN-4973-1
June 01, 2021

python3.8 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS

Summary:

Python could allow unintended access to network services.

Software Description:
- python3.8: An interactive high-level object-oriented language

Details:

It was discovered that the Python stdlib ipaddress API incorrectly handled
octal strings. A remote attacker could possibly use this issue to perform a
wide variety of attacks, including bypassing certain access restrictions.

Update instructions:

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

Ubuntu 20.10:
python3.8 3.8.6-1ubuntu0.3
python3.8-minimal 3.8.6-1ubuntu0.3

Ubuntu 20.04 LTS:
python3.8 3.8.5-1~20.04.3
python3.8-minimal 3.8.5-1~20.04.3

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

References:
  https://ubuntu.com/security/notices/USN-4973-1
CVE-2021-29921

Package Information:
  https://launchpad.net/ubuntu/+source/python3.8/3.8.6-1ubuntu0.3
  https://launchpad.net/ubuntu/+source/python3.8/3.8.5-1~20.04.3