Medium

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

Type: advisorySource: Official CVE List1 source record

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.

Announced 18 Feb 2025Source revision 1

Original source ↗

CVE-2025-26465

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2025-26465

Red Hat Enterprise Linux 8

Source reference: /containers/cna/affected/1/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 8

Source reference: /containers/cna/affected/2/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 9

Source reference: /containers/cna/affected/3/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 9

Source reference: /containers/cna/affected/4/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 9.4 Extended Update Support

Source reference: /containers/cna/affected/5/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Discovery 1.14

Source reference: /containers/cna/affected/6/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 10

Source reference: /containers/cna/affected/7/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 6

Source reference: /containers/cna/affected/8/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 7

Source reference: /containers/cna/affected/9/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat OpenShift Container Platform 4

Source reference: /containers/cna/affected/10/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://anongit.mindrot.org/openssh.git",
    "versions": [
      {
        "status": "affected",
        "version": "6.8p1",
        "versionType": "custom",
        "lessThanOrEqual": "9.9p1"
      }
    ],
    "packageName": "OpenSSH",
    "collectionURL": "https://www.openssh.com/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:enterprise_linux:8::appstream",
      "cpe:/o:redhat:enterprise_linux:8::baseos"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.0p1-26.el8_10",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:enterprise_linux:8::appstream",
      "cpe:/o:redhat:enterprise_linux:8::baseos"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.0p1-26.el8_10",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:enterprise_linux:9::appstream",
      "cpe:/o:redhat:enterprise_linux:9::baseos"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.7p1-45.el9",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:enterprise_linux:9::appstream",
      "cpe:/o:redhat:enterprise_linux:9::baseos"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.7p1-45.el9",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_eus:9.4::appstream",
      "cpe:/o:redhat:rhel_eus:9.4::baseos"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9.4 Extended Update Support",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.7p1-38.el9_4.5",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:discovery:1.14::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Discovery 1.14",
    "versions": [
      {
        "status": "unaffected",
        "version": "1.14.3-1748529279",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "discovery/discovery-server-rhel9",
    "collectionURL": "https://catalog.redhat.com/software/containers/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:10"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 10",
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:6"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 6",
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unknown"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:7"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 7",
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unknown"
  },
  {
    "cpes": [
      "cpe:/a:redhat:openshift:4"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat OpenShift Container Platform 4",
    "packageName": "openshift/ose-rhel-coreos-9",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  }
]

Related CVEs: CVE-2025-26465
Source reference: /cveMetadata/cveId

Publisher severity

medium

Source reference: /containers/cna/metrics

Event: #49445 · Revision 1
Added to Heist Feed: Sun, 25 Oct 2026 13:50:02 GMT
Publisher date: Tue, 18 Feb 2025 18:27:16 GMT

Read the original announcement