A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. A machine-in-the-middle attack can be performed by a malicious machine impersonating a legit server. This issue occurs due to how OpenSSH mishandles error codes in specific conditions when verifying the host key. For an attack to be considered successful, the attacker needs to manage to exhaust the client's memory resource first, turning the attack complexity high.
CVE-2025-26465
CVSS base score
6.8 (v3.1)
Severity
MEDIUM
Attack vector
Network
Weakness
CWE-390
Last modified
November 5, 2026
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Affected products
openbsd openssh
netapp active iq unified manager
netapp ontap
redhat openshift container platform
debian debian linux
redhat enterprise linux
References
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com
- access.redhat.com Third Party Advisory
- access.redhat.com
- bugzilla.redhat.com Issue Tracking, Third Party Advisory
- seclists.org Mailing List, Third Party Advisory
- seclists.org
- seclists.org