SB2025021815 - Multiple vulnerabilities in OpenBSD sshd and ssh client

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Input validation error (CVE-ID: CVE-2025-26466)

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input related to SSH2_MSG_PING handling in sshd(8). A remote attacker can send specially crafted packets to the server and perform a denial of service (DoS) attack.

2) Man-in-the-Middle (MitM) attack (CVE-ID: CVE-2025-26465)

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to incorrect processing of user-supplied data in ssh(1). A remote attacker can perform server impersonation when VerifyHostKeyDNS enabled.

Remediation

Install update from vendor's website.

References

• http://www.openbsd.org/errata76.html#008
• http://www.openbsd.org/errata75.html#017