USN-8051-2: libssh vulnerabilities

Publication date

23 February 2026

Overview

Several security issues were fixed in libssh.


Packages

  • libssh - A tiny C SSH library

Details

USN-8051-1 fixed vulnerabilities in libssh. This update provides the
corresponding updates for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu
20.04 LTS.

Original advisory details:

It was discovered that libssh clients incorrectly handled the key exchange
process. A remote attacker could possibly use this issue to cause libssh
clients to crash, resulting in a denial of service. (CVE-2025-8277)

It was discovered that the libssh SCP client incorrectly sanitized paths
received from servers. A remote attacker could use this issue to cause
libssh SCP clients to overwrite files outside of the working directory and
possibly execute arbitrary code. (CVE-2026-0964)

It was discovered that libssh incorrectly handled parsing configuration
files. A local attacker could possibly use this issue to cause libssh to
access non-regular files, resulting...

USN-8051-1 fixed vulnerabilities in libssh. This update provides the
corresponding updates for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu
20.04 LTS.

Original advisory details:

It was discovered that libssh clients incorrectly handled the key exchange
process. A remote attacker could possibly use this issue to cause libssh
clients to crash, resulting in a denial of service. (CVE-2025-8277)

It was discovered that the libssh SCP client incorrectly sanitized paths
received from servers. A remote attacker could use this issue to cause
libssh SCP clients to overwrite files outside of the working directory and
possibly execute arbitrary code. (CVE-2026-0964)

It was discovered that libssh incorrectly handled parsing configuration
files. A local attacker could possibly use this issue to cause libssh to
access non-regular files, resulting in a denial of service. (CVE-2026-0965)

It was discovered that libssh incorrectly handled the ssh_get_hexa()
function. A remote attacker could possibly use this issue to cause libssh
to crash, resulting in a denial of service. (CVE-2026-0966)

It was discovered that libssh incorrectly handled certain regular
expressions. A local attacker could possibly use this issue to cause
libssh to consume resources, resulting in a denial of service.
(CVE-2026-0967)

It was discovered that the libssh SFTP client incorrectly handled certain
malformed longname fields. A remote attacker could use this issue to cause
libssh SFTP clients to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2026-0968)


Update instructions

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

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
20.04 LTS focal libssh-4 –  0.9.3-2ubuntu2.5+esm3  
18.04 LTS bionic libssh-4 –  0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6  
16.04 LTS xenial libssh-4 –  0.6.3-4.3ubuntu0.6+esm4  

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