A Python security update has been released for Ubuntu Linux 12.04 ESM, 14.04 ESM, 16.04 LTS and 18.04 LTS.

USN-4581-1: Python vulnerability

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Ubuntu Security Notice USN-4581-1
October 14, 2020

python2.7, python3.4, python3.5, python3.6 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

Python could be used to perform a CRLF injection if it received a specially crafted request.

Software Description:
- python2.7: An interactive high-level object-oriented language
- python3.6: An interactive high-level object-oriented language
- python3.5: An interactive high-level object-oriented language
- python3.4: An interactive high-level object-oriented language

Details:

It was discovered that Python incorrectly handled certain character
sequences. A remote attacker could possibly use this issue to perform
CRLF injection.

Update instructions:

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

Ubuntu 18.04 LTS:
python2.7 2.7.17-1~18.04ubuntu1.2
python2.7-minimal 2.7.17-1~18.04ubuntu1.2
python3.6 3.6.9-1~18.04ubuntu1.3
python3.6-minimal 3.6.9-1~18.04ubuntu1.3

Ubuntu 16.04 LTS:
python2.7 2.7.12-1ubuntu0~16.04.13
python2.7-minimal 2.7.12-1ubuntu0~16.04.13
python3.5 3.5.2-2ubuntu0~16.04.12
python3.5-minimal 3.5.2-2ubuntu0~16.04.12

Ubuntu 14.04 ESM:
python2.7 2.7.6-8ubuntu0.6+esm7
python2.7-minimal 2.7.6-8ubuntu0.6+esm7
python3.4 3.4.3-1ubuntu1~14.04.7+esm8
python3.4-minimal 3.4.3-1ubuntu1~14.04.7+esm8

Ubuntu 12.04 ESM:
python2.7 2.7.3-0ubuntu3.19
python2.7-minimal 2.7.3-0ubuntu3.19

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

References:
  https://usn.ubuntu.com/4581-1
CVE-2020-26116

Package Information:
  https://launchpad.net/ubuntu/+source/python2.7/2.7.17-1~18.04ubuntu1.2
  https://launchpad.net/ubuntu/+source/python3.6/3.6.9-1~18.04ubuntu1.3
  https://launchpad.net/ubuntu/+source/python2.7/2.7.12-1ubuntu0~16.04.13
  https://launchpad.net/ubuntu/+source/python3.5/3.5.2-2ubuntu0~16.04.12