libssh vulnerabilities

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)