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.
References
Link Providers
http://seclists.org/fulldisclosure/2025/Feb/18 cve-icon
http://seclists.org/fulldisclosure/2025/May/7 cve-icon
http://seclists.org/fulldisclosure/2025/May/8 cve-icon
https://access.redhat.com/errata/RHSA-2025:16823 cve-icon cve-icon
https://access.redhat.com/errata/RHSA-2025:3837 cve-icon cve-icon
https://access.redhat.com/errata/RHSA-2025:6993 cve-icon cve-icon
https://access.redhat.com/errata/RHSA-2025:8385 cve-icon cve-icon
https://access.redhat.com/security/cve/CVE-2025-26465 cve-icon cve-icon
https://access.redhat.com/solutions/7109879 cve-icon cve-icon
https://blog.qualys.com/vulnerabilities-threat-research/2025/02/18/qualys-tru-discovers-two-vulnerabilities-in-openssh-cve-2025-26465-cve-2025-26466 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2344780 cve-icon cve-icon
https://bugzilla.suse.com/show_bug.cgi?id=1237040 cve-icon
https://ftp.openbsd.org/pub/OpenBSD/patches/7.6/common/008_ssh.patch.sig cve-icon
https://lists.debian.org/debian-lts-announce/2025/02/msg00020.html cve-icon
https://lists.mindrot.org/pipermail/openssh-unix-announce/2025-February/000161.html cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-26465 cve-icon
https://seclists.org/oss-sec/2025/q1/144 cve-icon cve-icon cve-icon cve-icon
https://security-tracker.debian.org/tracker/CVE-2025-26465 cve-icon
https://security.netapp.com/advisory/ntap-20250228-0003/ cve-icon
https://ubuntu.com/security/CVE-2025-26465 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-26465 cve-icon
https://www.openssh.com/releasenotes.html#9.9p2 cve-icon
https://www.openwall.com/lists/oss-security/2025/02/18/1 cve-icon
https://www.openwall.com/lists/oss-security/2025/02/18/4 cve-icon
https://www.theregister.com/2025/02/18/openssh_vulnerabilities_mitm_dos/ cve-icon
https://www.vicarius.io/vsociety/posts/cve-2025-26465-detect-vulnerable-openssh cve-icon
https://www.vicarius.io/vsociety/posts/cve-2025-26465-mitigate-vulnerable-openssh cve-icon
History

Mon, 03 Nov 2025 22:30:00 +0000

Type Values Removed Values Added
References

Mon, 03 Nov 2025 20:30:00 +0000


Thu, 23 Oct 2025 02:45:00 +0000

Type Values Removed Values Added
References

Fri, 26 Sep 2025 06:45:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
cpe:/o:redhat:enterprise_linux:8::baseos
References

Mon, 02 Jun 2025 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat discovery
CPEs cpe:/a:redhat:discovery:1.14::el9
Vendors & Products Redhat discovery
References

Tue, 27 May 2025 15:45:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10

Wed, 14 May 2025 03:00:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:enterprise_linux:9

Tue, 13 May 2025 09:15:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:9 cpe:/a:redhat:enterprise_linux:9::appstream
cpe:/o:redhat:enterprise_linux:9::baseos
References

Tue, 15 Apr 2025 03:15:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_eus:9.4

Mon, 14 Apr 2025 11:45:00 +0000

Type Values Removed Values Added
First Time appeared Debian
Debian debian Linux
Netapp
Netapp active Iq Unified Manager
Netapp ontap
Openbsd
Openbsd openssh
Redhat openshift Container Platform
CPEs cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
cpe:2.3:a:netapp:ontap:9:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:6.8:p1:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:9.9:-:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:9.9:p1:*:*:*:*:*:*
cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
Vendors & Products Debian
Debian debian Linux
Netapp
Netapp active Iq Unified Manager
Netapp ontap
Openbsd
Openbsd openssh
Redhat openshift Container Platform

Mon, 14 Apr 2025 11:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_eus:9.4::appstream
cpe:/o:redhat:rhel_eus:9.4::baseos
Vendors & Products Redhat rhel Eus
References

Mon, 03 Mar 2025 18:45:00 +0000


Fri, 28 Feb 2025 13:45:00 +0000

Type Values Removed Values Added
References

Wed, 19 Feb 2025 15:15:00 +0000

Type Values Removed Values Added
References
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 19 Feb 2025 14:00:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 19 Feb 2025 05:30:00 +0000


Tue, 18 Feb 2025 19:45:00 +0000

Type Values Removed Values Added
References

Tue, 18 Feb 2025 18:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-390
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published: 2025-02-18T18:27:16.843Z

Updated: 2025-11-03T21:12:55.938Z

Reserved: 2025-02-10T18:31:47.978Z

Link: CVE-2025-26465

cve-icon Vulnrichment

Updated: 2025-03-03T17:48:15.682Z

cve-icon NVD

Status : Modified

Published: 2025-02-18T19:15:29.230

Modified: 2025-11-03T22:18:41.727

Link: CVE-2025-26465

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-02-17T00:00:00Z

Links: CVE-2025-26465 - Bugzilla