USN-3199-1: Python Crypto vulnerability

Ubuntu Security Notice USN-3199-1

16th February, 2017

Python Crypto vulnerability

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

  • Ubuntu 16.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS


Programs using the Python Cryptography Toolkit could be made to crash or run programs if they receive specially crafted network traffic or other input.

Software description

  • python-crypto - cryptographic algorithms and protocols for Python


It was discovered that the ALGnew function in block_templace.c in the Python
Cryptography Toolkit contained a heap-based buffer overflow vulnerability.
A remote attacker could use this flaw to execute arbitrary code by using
a crafted initialization vector parameter.

Update instructions

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

Ubuntu 16.10:
python3-crypto 2.6.1-6ubuntu0.16.10.2
python-crypto 2.6.1-6ubuntu0.16.10.2
Ubuntu 16.04 LTS:
python3-crypto 2.6.1-6ubuntu0.16.04.1
python-crypto 2.6.1-6ubuntu0.16.04.1
Ubuntu 14.04 LTS:
python3-crypto 2.6.1-4ubuntu0.1
python-crypto 2.6.1-4ubuntu0.1

To update your system, please follow these instructions:

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