CVE-2025-26465
Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled
CVSS Score
6.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-390 |
| Published | Feb 18, 2025 |
| Last Updated | Jan 29, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support
All versions affected Red Hat / Red Hat Discovery 1.14
All versions affected Red Hat / Red Hat Enterprise Linux 10
All versions affected Red Hat / Red Hat Enterprise Linux 6
All versions affected Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat OpenShift Container Platform 4
All versions affected References
access.redhat.com: https://access.redhat.com/errata/RHSA-2025:16823 access.redhat.com: https://access.redhat.com/errata/RHSA-2025:3837 access.redhat.com: https://access.redhat.com/errata/RHSA-2025:6993 access.redhat.com: https://access.redhat.com/errata/RHSA-2025:8385 access.redhat.com: https://access.redhat.com/security/cve/CVE-2025-26465 access.redhat.com: https://access.redhat.com/solutions/7109879 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2344780 seclists.org: https://seclists.org/oss-sec/2025/q1/144 lists.debian.org: https://lists.debian.org/debian-lts-announce/2025/02/msg00020.html openwall.com: https://www.openwall.com/lists/oss-security/2025/02/18/1 openwall.com: https://www.openwall.com/lists/oss-security/2025/02/18/4 theregister.com: https://www.theregister.com/2025/02/18/openssh_vulnerabilities_mitm_dos/ bugzilla.suse.com: https://bugzilla.suse.com/show_bug.cgi?id=1237040 security-tracker.debian.org: https://security-tracker.debian.org/tracker/CVE-2025-26465 ftp.openbsd.org: https://ftp.openbsd.org/pub/OpenBSD/patches/7.6/common/008_ssh.patch.sig ubuntu.com: https://ubuntu.com/security/CVE-2025-26465 openssh.com: https://www.openssh.com/releasenotes.html#9.9p2 blog.qualys.com: https://blog.qualys.com/vulnerabilities-threat-research/2025/02/18/qualys-tru-discovers-two-vulnerabilities-in-openssh-cve-2025-26465-cve-2025-26466 lists.mindrot.org: https://lists.mindrot.org/pipermail/openssh-unix-announce/2025-February/000161.html security.netapp.com: https://security.netapp.com/advisory/ntap-20250228-0003/ vicarius.io: https://www.vicarius.io/vsociety/posts/cve-2025-26465-detect-vulnerable-openssh vicarius.io: https://www.vicarius.io/vsociety/posts/cve-2025-26465-mitigate-vulnerable-openssh seclists.org: http://seclists.org/fulldisclosure/2025/May/8 seclists.org: http://seclists.org/fulldisclosure/2025/May/7 seclists.org: http://seclists.org/fulldisclosure/2025/Feb/18