USN-7270-1: OpenSSH vulnerabilities

Releases

• Ubuntu 24.10
• Ubuntu 24.04 LTS
• Ubuntu 22.04 LTS
• Ubuntu 20.04 LTS

Packages

• openssh - secure shell (SSH) for secure access to remote machines

Details

It was discovered that the OpenSSH client incorrectly handled the
non-default VerifyHostKeyDNS option. If that option were enabled, an
attacker could possibly impersonate a server by completely bypassing the
server identity check. (CVE-2025-26465)

It was discovered that OpenSSH incorrectly handled the transport-level ping
facility. A remote attacker could possibly use this issue to cause OpenSSH
clients and servers to consume resources, leading to a denial of service.
This issue only affected Ubuntu 24.04 LTS and Ubuntu 24.10.
(CVE-2025-26466)

Update instructions

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

Ubuntu 24.10

• openssh-client - 1:9.7p1-7ubuntu4.2
• openssh-server - 1:9.7p1-7ubuntu4.2

Ubuntu 24.04

• openssh-client - 1:9.6p1-3ubuntu13.8
• openssh-server - 1:9.6p1-3ubuntu13.8

Ubuntu 22.04

• openssh-client - 1:8.9p1-3ubuntu0.11
• openssh-server - 1:8.9p1-3ubuntu0.11

Ubuntu 20.04

• openssh-client - 1:8.2p1-4ubuntu0.12
• openssh-server - 1:8.2p1-4ubuntu0.12

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

References

• CVE-2025-26465
• CVE-2025-26466

Related notices

• USN-7270-2