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6.8Medium

Openbsd Openssh

CVE-2025-26465

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.

What this means for your business

  • It affects Openbsd Openssh. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it remotely, over a network, without a login, but only after tricking someone into an action such as opening a file or a link.

What to do

  1. 1Check whether your company or your suppliers run Openbsd Openssh, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposedBook a call

Scoring

CVSS
6.8 (v3.1)
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-390
Assigned by
secalert@redhat.com

Dates

Published
2025-02-18
Last modified
2026-09-02
Sources
NVD

Affected products

  • Openbsd Openssh6.9 - 9.8, 6.8, 9.9
  • Netapp Active Iq Unified Managerall versions
  • Netapp Ontap9
  • Redhat Openshift Container Platform4.0
  • Debian Debian Linux11.0, 12.0
  • Redhat Enterprise Linux9.0

As listed in the NVD configuration data. Not a statement about your estate.

References