High

Corosync: corosync: heap-based buffer overflow in totempg assembly buffer during fragmented message reassembly

Type: advisorySource: Official CVE List1 source record

A heap-based buffer overflow was found in Corosync's Totem Process Group (totempg) message reassembly. When processing fragmented multicast messages, the buffer used to reassemble fragments lacks a runtime bounds check in release builds. A network-adjacent attacker able to send crafted multicast protocol messages to the cluster could cause a heap buffer overflow with attacker-controlled data. This can crash the Corosync daemon, causing a denial of service to the entire cluster, and may potentially allow further exploitation given sufficient heap-corruption control.

Announced 4 Sept 2026Group revision 1

Original source ↗

CVE-2026-81665

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-2026-81665

Red Hat Enterprise Linux 10

Source reference: /containers/cna/affected/0/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 10.0 Extended Update Support

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 7 Extended Lifecycle Support

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 8

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 8.4 Advanced Mission Critical Update Support

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 8.4 Extended Update Support Long-Life Add-On

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 8.6 Advanced Mission Critical Update Support

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 8.6 Extended Update Support Long-Life Add-On

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 8.8 Telecommunications Update Service

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 8.8 Update Services for SAP Solutions

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 Enterprise Linux 9

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

Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Source reference: /containers/cna/affected/11/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 Update Services for SAP Solutions

Source reference: /containers/cna/affected/12/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 9.6 Extended Update Support

Source reference: /containers/cna/affected/13/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/14/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/15/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.

[
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:10.2"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 10",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.10-1.el10_2.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux_eus:10.0"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 10.0 Extended Update Support",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.9-1.el10_0.3",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:7::server"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 7 Extended Lifecycle Support",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:2.4.5-7.el7_9.4",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:enterprise_linux:8::appstream",
      "cpe:/a:redhat:enterprise_linux:8::crb",
      "cpe:/a:redhat:enterprise_linux:8::highavailability",
      "cpe:/a:redhat:enterprise_linux:8::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.8-1.el8_10.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_aus:8.4::appstream",
      "cpe:/a:redhat:rhel_aus:8.4::highavailability",
      "cpe:/a:redhat:rhel_eus_long_life:8.4::appstream",
      "cpe:/a:redhat:rhel_eus_long_life:8.4::highavailability",
      "cpe:/a:redhat:rhel_eus_long_life:8.4::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.0-3.el8_4.3",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_aus:8.4::appstream",
      "cpe:/a:redhat:rhel_aus:8.4::highavailability",
      "cpe:/a:redhat:rhel_eus_long_life:8.4::appstream",
      "cpe:/a:redhat:rhel_eus_long_life:8.4::highavailability",
      "cpe:/a:redhat:rhel_eus_long_life:8.4::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.0-3.el8_4.3",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_aus:8.6::appstream",
      "cpe:/a:redhat:rhel_eus_long_life:8.6::appstream",
      "cpe:/a:redhat:rhel_eus_long_life:8.6::highavailability",
      "cpe:/a:redhat:rhel_eus_long_life:8.6::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.5-2.el8_6.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_aus:8.6::appstream",
      "cpe:/a:redhat:rhel_eus_long_life:8.6::appstream",
      "cpe:/a:redhat:rhel_eus_long_life:8.6::highavailability",
      "cpe:/a:redhat:rhel_eus_long_life:8.6::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.5-2.el8_6.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_e4s:8.8::appstream",
      "cpe:/a:redhat:rhel_e4s:8.8::highavailability",
      "cpe:/a:redhat:rhel_tus:8.8::appstream",
      "cpe:/a:redhat:rhel_tus:8.8::highavailability"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8.8 Telecommunications Update Service",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.7-1.el8_8.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_e4s:8.8::appstream",
      "cpe:/a:redhat:rhel_e4s:8.8::highavailability",
      "cpe:/a:redhat:rhel_tus:8.8::appstream",
      "cpe:/a:redhat:rhel_tus:8.8::highavailability"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.7-1.el8_8.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:enterprise_linux:9::appstream",
      "cpe:/a:redhat:enterprise_linux:9::crb",
      "cpe:/a:redhat:enterprise_linux:9::highavailability",
      "cpe:/a:redhat:enterprise_linux:9::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.10-1.el9_8.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_e4s:9.2::appstream",
      "cpe:/a:redhat:rhel_e4s:9.2::highavailability",
      "cpe:/a:redhat:rhel_e4s:9.2::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.7-1.el9_2.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_e4s:9.4::appstream",
      "cpe:/a:redhat:rhel_e4s:9.4::highavailability",
      "cpe:/a:redhat:rhel_e4s:9.4::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.8-1.el9_4.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:rhel_eus:9.6::appstream",
      "cpe:/a:redhat:rhel_eus:9.6::crb",
      "cpe:/a:redhat:rhel_eus:9.6::highavailability",
      "cpe:/a:redhat:rhel_eus:9.6::resilientstorage"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9.6 Extended Update Support",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:3.1.9-2.el9_6.2",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "corosync",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "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"
  },
  {
    "cpes": [
      "cpe:/a:redhat:openshift:4"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat OpenShift Container Platform 4",
    "packageName": "rhcos",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  }
]

Related CVEs: CVE-2026-81665
Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event: #49474 · Revision 1
Added to Heist Feed: Sun, 25 Oct 2026 13:50:23 GMT
Publisher date: Fri, 04 Sep 2026 09:05:35 GMT

Read the original announcement

Revision history

25 Oct 2026CVE-2026-81665 · Revision 1Source updated