A libssh security update has been released for Ubuntu Linux 19.10 and 18.04 LTS.

USN-4327-1: libssh vulnerability

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Ubuntu Security Notice USN-4327-1
April 09, 2020

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

- Ubuntu 19.10
- Ubuntu 18.04 LTS

Summary:

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

Software Description:
- libssh: A tiny C SSH library

Details:

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

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

References:
https://usn.ubuntu.com/4327-1
CVE-2020-1730

Package Information:
https://launchpad.net/ubuntu/+source/libssh/0.9.0-1ubuntu1.4
https://launchpad.net/ubuntu/+source/libssh/0.8.0~20170825.94fa1e38-1ubuntu0.6