CVE-2025-26465

6.8 MEDIUM
Published: February 18, 2025 Modified: November 03, 2025

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://access.redhat.com/security/cve/CVE-2025-26465
Source: secalert@redhat.com
Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2344780
Source: secalert@redhat.com
Issue Tracking Third Party Advisory
https://seclists.org/oss-sec/2025/q1/144
Source: secalert@redhat.com
Mailing List Third Party Advisory
http://seclists.org/fulldisclosure/2025/Feb/18
Source: af854a3a-2127-422b-91ae-364da2661108
http://seclists.org/fulldisclosure/2025/May/7
Source: af854a3a-2127-422b-91ae-364da2661108
http://seclists.org/fulldisclosure/2025/May/8
Source: af854a3a-2127-422b-91ae-364da2661108
https://bugzilla.suse.com/show_bug.cgi?id=1237040
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking
https://ftp.openbsd.org/pub/OpenBSD/patches/7.6/common/008_ssh.patch.sig
Source: af854a3a-2127-422b-91ae-364da2661108
Patch
https://lists.debian.org/debian-lts-announce/2025/02/msg00020.html
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://lists.mindrot.org/pipermail/openssh-unix-announce/2025-February/000161.html
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2025-26465
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://security.netapp.com/advisory/ntap-20250228-0003/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://ubuntu.com/security/CVE-2025-26465
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.openssh.com/releasenotes.html#9.9p2
Source: af854a3a-2127-422b-91ae-364da2661108
Release Notes
https://www.openwall.com/lists/oss-security/2025/02/18/1
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://www.openwall.com/lists/oss-security/2025/02/18/4
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://www.theregister.com/2025/02/18/openssh_vulnerabilities_mitm_dos/
Source: af854a3a-2127-422b-91ae-364da2661108
Press/Media Coverage
https://www.vicarius.io/vsociety/posts/cve-2025-26465-detect-vulnerable-openssh
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.vicarius.io/vsociety/posts/cve-2025-26465-mitigate-vulnerable-openssh
Source: af854a3a-2127-422b-91ae-364da2661108
Mitigation Third Party Advisory
https://seclists.org/oss-sec/2025/q1/144
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mailing List Third Party Advisory

26 reference(s) from NVD

Quick Stats

CVSS v3 Score
6.8 / 10.0
EPSS (Exploit Probability)
64.4%
98th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

openbsd debian redhat netapp