CVE-2025-26465

Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled

MEDIUM
6.8
CVSS Score
Published: February 18, 2025 at 06:27 PM UTC
Updated: October 21, 2026 at 09:17 PM UTC
10 products affected across 5 vendorsDebian LinuxEnterprise LinuxActive IQ Unified Manager

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Severity
MEDIUM6.8
Exploit prediction
EPSS 8%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 0:8.0p1-26.el8_10 (unaffected)
Vendor states this is fixed in 0:8.7p1-38.el9_4.5 (unaffected)
Vendor states this is fixed in 0:8.7p1-45.el9 (unaffected)
Vendor states this is fixed in 10 (unaffected)
Vendor states this is fixed in 6 (unknown)
Vendor states this is fixed in 7 (unknown)
v < V7.26.0310
Affected range stops below V7.26.0310, so it looks safe — our inference, not a vendor statement

References (27)

VDB Entryx_refsource_REDHATThird Party Advisory
https://access.redhat.com/security/cve/CVE-2025-26465
Issue Trackingx_refsource_REDHATThird Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2344780
Mailing ListThird Party Advisory
https://seclists.org/oss-sec/2025/q1/144
Issue Tracking
Source: af854a3a-2127-422b-91ae-364da2661108
https://bugzilla.suse.com/show_bug.cgi?id=1237040

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.8MEDIUMredhat
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-390

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