USN-1965-1: pyOpenSSL vulnerability

Ubuntu Security Notice USN-1965-1

23rd September, 2013

pyopenssl vulnerability

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

  • Ubuntu 13.04
  • Ubuntu 12.10
  • Ubuntu 12.04 LTS
  • Ubuntu 10.04 LTS


Fraudulent security certificates could allow sensitive information to be exposed when accessing the Internet.

Software description

  • pyopenssl - Python wrapper around the OpenSSL library


It was discovered that pyOpenSSL did not properly handle certificates with
NULL characters in the Subject Alternative Name field. An attacker could
exploit this to perform a man in the middle attack to view sensitive
information or alter encrypted communications.

Update instructions

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

Ubuntu 13.04:
python3-openssl 0.13-2ubuntu3.1
python-openssl 0.13-2ubuntu3.1
Ubuntu 12.10:
python3-openssl 0.13-2ubuntu1.1
python-openssl 0.13-2ubuntu1.1
Ubuntu 12.04 LTS:
python-openssl 0.12-1ubuntu2.1
Ubuntu 10.04 LTS:
python-openssl 0.10-1ubuntu0.1

To update your system, please follow these instructions:

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