The following updates has been released for Ubuntu Linux:

USN-3795-1: libssh vulnerability
USN-3796-1: Paramiko vulnerability
USN-3796-2: Paramiko vulnerability

USN-3795-1: libssh vulnerability

==========================================================================
Ubuntu Security Notice USN-3795-1
October 17, 2018

libssh vulnerability
==========================================================================

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

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

libssh could allow unintended access to network services.

Software Description:
- libssh: A tiny C SSH library

Details:

Peter Winter-Smith discovered that libssh incorrectly handled
authentication when being used as a server. A remote attacker could use
this issue to bypass authentication without any credentials.

Update instructions:

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

Ubuntu 18.04 LTS:
libssh-4 0.8.0~20170825.94fa1e38-1ubuntu0.1

Ubuntu 16.04 LTS:
libssh-4 0.6.3-4.3ubuntu0.1

Ubuntu 14.04 LTS:
libssh-4 0.6.1-0ubuntu3.4

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
https://usn.ubuntu.com/usn/usn-3795-1
CVE-2018-10933

Package Information:
https://launchpad.net/ubuntu/+source/libssh/0.8.0~20170825.94fa1e38-1ubuntu0.1
https://launchpad.net/ubuntu/+source/libssh/0.6.3-4.3ubuntu0.1
https://launchpad.net/ubuntu/+source/libssh/0.6.1-0ubuntu3.4

USN-3796-1: Paramiko vulnerability

==========================================================================
Ubuntu Security Notice USN-3796-1
October 17, 2018

paramiko vulnerability
==========================================================================

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

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Paramiko could allow unintended access to network services.

Software Description:
- paramiko: Python SSH2 library

Details:

Daniel Hoffman discovered that Paramiko incorrectly handled authentication
when being used as a server. A remote attacker could use this issue to
bypass authentication without any credentials.

Update instructions:

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

Ubuntu 18.04 LTS:
python-paramiko 2.0.0-1ubuntu1.1
python3-paramiko 2.0.0-1ubuntu1.1

Ubuntu 16.04 LTS:
python-paramiko 1.16.0-1ubuntu0.2
python3-paramiko 1.16.0-1ubuntu0.2

Ubuntu 14.04 LTS:
python-paramiko 1.10.1-1git1ubuntu0.2

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
https://usn.ubuntu.com/usn/usn-3796-1
CVE-2018-1000805

Package Information:
https://launchpad.net/ubuntu/+source/paramiko/2.0.0-1ubuntu1.1
https://launchpad.net/ubuntu/+source/paramiko/1.16.0-1ubuntu0.2
https://launchpad.net/ubuntu/+source/paramiko/1.10.1-1git1ubuntu0.2

USN-3796-2: Paramiko vulnerability

==========================================================================
Ubuntu Security Notice USN-3796-2
October 17, 2018

paramiko vulnerability
==========================================================================

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

- Ubuntu 12.04 ESM

Summary:

Paramiko could allow unintended access to network services.

Software Description:
- paramiko: Python SSH2 library

Details:

USN-3796-1 fixed a vulnerability in paramiko. This update provides
the corresponding update for Ubuntu 12.04 ESM.

Original advisory details:

Daniel Hoffman discovered that Paramiko incorrectly handled
 authentication when being used as a server. A remote attacker could
 use this issue to bypass authentication without any credentials.

Update instructions:

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

Ubuntu 12.04 ESM:
  python-paramiko 1.7.7.1-2ubuntu1.2

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://usn.ubuntu.com/usn/usn-3796-2
  https://usn.ubuntu.com/usn/usn-3796-1
  CVE-2018-1000805