USN-4327-1: libssh vulnerability

9 April 2020

libssh vulnerability

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

  • Ubuntu 19.10
  • Ubuntu 18.04 LTS


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

Software Description

  • libssh - A tiny C SSH library


Yasheng Yang discovered that libssh incorrectly handled AES-CTR ciphers. A remote attacker could possibly use this issue 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 19.10
libssh-4 - 0.9.0-1ubuntu1.4
Ubuntu 18.04 LTS
libssh-4 - 0.8.0~20170825.94fa1e38-1ubuntu0.6

To update your system, please follow these instructions:

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