A python-cryptography security update has been released for Ubuntu 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

USN-4613-1: python-cryptography vulnerability

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Ubuntu Security Notice USN-4613-1
November 03, 2020

python-cryptography vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

python-cryptography could be made to expose sensitive information over the
network.

Software Description:
- python-cryptography: Cryptography Python library

Details:

Hubert Kario discovered that python-cryptography incorrectly handled certain decryption.
An attacker could possibly use this issue to expose sensitive information.

Update instructions:

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

Ubuntu 20.10:
python3-cryptography 3.0-1ubuntu0.1

Ubuntu 20.04 LTS:
python-cryptography 2.8-3ubuntu0.1
python3-cryptography 2.8-3ubuntu0.1

Ubuntu 18.04 LTS:
python-cryptography 2.1.4-1ubuntu1.4
python3-cryptography 2.1.4-1ubuntu1.4

Ubuntu 16.04 LTS:
python-cryptography 1.2.3-1ubuntu0.3
python3-cryptography 1.2.3-1ubuntu0.3

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

References:
  https://usn.ubuntu.com/4613-1
CVE-2020-25659

Package Information:
  https://launchpad.net/ubuntu/+source/python-cryptography/3.0-1ubuntu0.1
  https://launchpad.net/ubuntu/+source/python-cryptography/2.8-3ubuntu0.1
  https://launchpad.net/ubuntu/+source/python-cryptography/2.1.4-1ubuntu1.4
  https://launchpad.net/ubuntu/+source/python-cryptography/1.2.3-1ubuntu0.3