[USN-8093-1] libssh vulnerability

[noreply+usn-bot at canonical.com]

==========================================================================
Ubuntu Security Notice USN-8093-1
March 16, 2026

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

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

- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

libssh could be made to crash or behave unexpectedly.

Software Description:
- libssh: A tiny C SSH library

Details:

It was discovered that libssh incorrectly performed bounds checking when
processing SFTP extensions. If a client application queried extension data out
of bounds, it could cause the application to crash, resulting in a denial of
service, or exhibit unintended behavior.

Update instructions:

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

Ubuntu 25.10
  libssh-4                        0.11.2-1ubuntu0.3

Ubuntu 24.04 LTS
  libssh-4                        0.10.6-2ubuntu0.4
  libssh-gcrypt-4                 0.10.6-2ubuntu0.4

Ubuntu 22.04 LTS
  libssh-4                        0.9.6-2ubuntu0.22.04.7
  libssh-gcrypt-4                 0.9.6-2ubuntu0.22.04.7

Ubuntu 20.04 LTS
  libssh-4                        0.9.3-2ubuntu2.5+esm4
                                  Available with Ubuntu Pro
  libssh-gcrypt-4                 0.9.3-2ubuntu2.5+esm4
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  libssh-4                        0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7
                                  Available with Ubuntu Pro
  libssh-gcrypt-4                 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  libssh-4                        0.6.3-4.3ubuntu0.6+esm5
                                  Available with Ubuntu Pro
  libssh-gcrypt-4                 0.6.3-4.3ubuntu0.6+esm5
                                  Available with Ubuntu Pro

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

References:
  https://ubuntu.com/security/notices/USN-8093-1
  CVE-2026-3731

Package Information:
  https://launchpad.net/ubuntu/+source/libssh/0.11.2-1ubuntu0.3
  https://launchpad.net/ubuntu/+source/libssh/0.10.6-2ubuntu0.4
  https://launchpad.net/ubuntu/+source/libssh/0.9.6-2ubuntu0.22.04.7
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