USN-1707-1: libssh vulnerability

28 January 2013

libssh vulnerability

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

  • Ubuntu 12.10
  • Ubuntu 12.04 LTS
  • Ubuntu 11.10
  • Ubuntu 10.04 LTS


libssh could be made to crash if it received specially crafted network traffic.

Software Description

  • libssh - A tiny C SSH library


Yong Chuan Koh discovered that libssh incorrectly handled certain negotiation requests. A remote attacker could use this to cause libssh to crash, resulting in a denial of service.

Update instructions

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

Ubuntu 12.10
libssh-4 - 0.5.2-1ubuntu0.12.10.2
Ubuntu 12.04 LTS
libssh-4 - 0.5.2-1ubuntu0.12.04.2
Ubuntu 11.10
libssh-4 - 0.5.2-1ubuntu0.11.10.2
Ubuntu 10.04 LTS
libssh-4 - 0.4.2-1ubuntu1.2

To update your system, please follow these instructions:

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