USN-2912-1: libssh vulnerabilities

23 February 2016

libssh vulnerabilities

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

  • Ubuntu 15.10
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


Several security issues were fixed in libssh.

Software Description

  • libssh - A tiny C SSH library


Mariusz Ziulek discovered that libssh incorrectly handled certain packets. A remote attacker could possibly use this issue to cause libssh to crash, resulting in a denial of service. (CVE-2015-3146)

Aris Adamantiadis discovered that libssh incorrectly generated ephemeral secret keys of 128 bits instead of the recommended 1024 or 2048 bits when using the diffie-hellman-group1 and diffie-hellman-group14 methods. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. (CVE-2016-0739)

Update instructions

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

Ubuntu 15.10
libssh-4 - 0.6.3-3ubuntu3.2
Ubuntu 14.04 LTS
libssh-4 - 0.6.1-0ubuntu3.3
Ubuntu 12.04 LTS
libssh-4 - 0.5.2-1ubuntu0.12.04.6

To update your system, please follow these instructions:

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