Medium

Openssh: denial-of-service in openssh

Type: advisorySource: Official CVE List1 source record

A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled increase in memory consumption on the server side. Consequently, the server may become unavailable, resulting in a denial of service attack.

Announced 28 Feb 2025Group revision 1

Original source ↗

CVE-2025-26466

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-2025-26466

Red Hat Enterprise Linux 10

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 9

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 6

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 7

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 Enterprise Linux 8

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 OpenShift Container Platform 4

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 OpenShift Container Platform 4

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

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://anongit.mindrot.org/openssh.git",
    "versions": [
      {
        "status": "affected",
        "version": "9.5p1",
        "versionType": "custom",
        "lessThanOrEqual": "9.9p1"
      }
    ],
    "packageName": "OpenSSH",
    "collectionURL": "https://www.openssh.com/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:10.0"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 10",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:9.9p1-7.el10_0",
        "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:/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": "unaffected"
  },
  {
    "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": "unaffected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8",
    "packageName": "openssh",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:openshift:4"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat OpenShift Container Platform 4",
    "packageName": "openshift/ose-rhel-coreos-8",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "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": "unaffected"
  }
]

Related CVEs: CVE-2025-26466
Source reference: /cveMetadata/cveId

Publisher severity

medium

Source reference: /containers/cna/metrics

Event: #49288 · Revision 1
Added to Heist Feed: Sun, 25 Oct 2026 13:47:50 GMT
Publisher date: Fri, 28 Feb 2025 21:25:28 GMT

Read the original announcement

Revision history

25 Oct 2026CVE-2025-26466 · Revision 1Source updated