Bug 2344780 (CVE-2025-26465) - CVE-2025-26465 openssh: Machine-in-the-middle attack if VerifyHostKeyDNS is enabled
Summary: CVE-2025-26465 openssh: Machine-in-the-middle attack if VerifyHostKeyDNS is e...
Keywords:
Status: NEW
Alias: CVE-2025-26465
Deadline: 2025-02-17
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-02-10 22:04 UTC by OSIDB Bzimport
Modified: 2026-02-25 09:30 UTC (History)
14 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2025:16823 0 None None None 2025-09-26 00:54:07 UTC
Red Hat Product Errata RHSA-2025:3837 0 None None None 2025-04-14 10:55:00 UTC
Red Hat Product Errata RHSA-2025:6993 0 None None None 2025-05-13 08:43:52 UTC

Description OSIDB Bzimport 2025-02-10 22:04:10 UTC
The OpenSSH client is vulnerable to an active machine-in-the-middle attack if the VerifyHostKeyDNS option is enabled (it is disabled by default): when a vulnerable client connects to a server, an active machine-in-the-middle can impersonate the server by completely bypassing the client's checks of the server's identity.

Comment 3 Sandipan Roy 2025-02-18 11:09:51 UTC
Making it Public as https://seclists.org/oss-sec/2025/q1/144

Comment 4 Klaas Demter 2025-02-19 09:39:34 UTC
I am reading that correctly on https://access.redhat.com/security/cve/CVE-2025-26465 -- there is no fix planned for rhel8 because it's a non-default config+moderate rating?

Comment 6 sakshi 2025-03-20 02:15:27 UTC
Regarding the CVE link mentioned below, the OpenSSH client must have the VerifyHostKeyDNS option enabled, which is disabled by default in Red Hat Enterprise Linux (RHEL).


https://access.redhat.com/security/cve/CVE-2025-26465#cve-affected-packages

Products / Services                         Components  State  Errata Release Date
```
Red Hat Enterprise Linux 9	              openssh   Affected		
Red Hat OpenShift Container Platform 4	       rhcos   Fix deferred	

If ` VerifyHostKeyDNS` option is disabled in RHEL 9, then why it's `affected` state.

Is there any timeline to fix this in RHCOS?

Comment 7 sakshi 2025-03-24 03:15:21 UTC
Customer is looking for update on my previous comment. Kindly assist. Thanks!

Comment 10 errata-xmlrpc 2025-04-14 10:54:58 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:3837 https://access.redhat.com/errata/RHSA-2025:3837

Comment 11 errata-xmlrpc 2025-05-13 08:43:49 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:6993 https://access.redhat.com/errata/RHSA-2025:6993

Comment 12 errata-xmlrpc 2025-09-26 00:54:05 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:16823 https://access.redhat.com/errata/RHSA-2025:16823

Comment 13 Helen Grace 2026-02-25 09:30:44 UTC
(In reply to sakshi from comment #6)
> Regarding the CVE link mentioned below, the OpenSSH client must have the
> VerifyHostKeyDNS option enabled, which is disabled by default in Red Hat
> Enterprise Linux (RHEL).
> 
> 
> https://access.redhat.com/security/cve/CVE-2025-26465#cve-affected-packages
https://holeonline.io/
> 
> Products / Services                         Components  State  Errata
> Release Date
> ```
> Red Hat Enterprise Linux 9	              openssh   Affected		
> Red Hat OpenShift Container Platform 4	       rhcos   Fix deferred	

Thanks for the clarification. While VerifyHostKeyDNS is disabled by default in RHEL, the package is still marked as Affected because the vulnerable code is present and can be triggered if the option is explicitly enabled.

This issue has since been addressed via RHSA-2025:6993 (RHEL 9) and RHSA-2025:16823 (RHEL 8). For RHCOS, fixes are typically aligned with the corresponding RHEL base and OpenShift release cycle.


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