Vulnerability-Lookup

CVE-2026-81666 (GCVE-0-2026-81666)

Vulnerability from cvelistv5 – Published: 2026-09-04 09:46 – Updated: 2026-09-08 14:41

Title

Corosync: corosync: integer overflow in check_memb_commit_token_sanity may bypass message length validation on 32-bit systems

Summary

An integer overflow was found in Corosync's handling of membership commit token messages. The length-validation check for these messages can be bypassed on 32-bit systems due to an integer overflow in the calculation of the expected message length, allowing a crafted network packet to trigger an out-of-bounds memory access that crashes the Corosync daemon. This results in a denial of service for the affected cluster node. The overflow does not occur on 64-bit systems, where the length calculation is correctly performed in 64-bit arithmetic.

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-08 14:41 UTC

CWE

CWE-190 - Integer Overflow or Wraparound

Assigner

redhat redhat root

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-81666	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2524923	issue-trackingx_refsource_REDHAT

Impacted products

5 products

Vendor	Product	Version
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9
Red Hat	Red Hat OpenShift Container Platform 4	cpe:/a:redhat:openshift:4

Date Public

2026-09-04 08:14

Credits

Red Hat would like to thank Tristan Madani (Talence Security) for reporting this issue.

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-81666

Vulnerability from fkie_nvd - Published: 2026-09-04 10:17 - Updated: 2026-09-08 19:08

Severity

6.5 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	secalert@redhat.com	https://access.redhat.com/security/cve/CVE-2026-81666
	secalert@redhat.com	https://bugzilla.redhat.com/show_bug.cgi?id=2524923

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-190"
        }
      ],
      "source": "secalert@redhat.com",
      "type": "Secondary"
    }
  ]
}

GHSA-8297-6G53-8GP5

Vulnerability from github – Published: 2026-09-04 12:30 – Updated: 2026-09-04 12:30

Details

Severity

6.5 (Medium)


                  
                    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-81666"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-190"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T10:17:13Z",
    "severity": "MODERATE"
  },
  "details": "An integer overflow was found in Corosync\u0027s handling of membership commit token messages. The length-validation check for these messages can be bypassed on 32-bit systems due to an integer overflow in the calculation of the expected message length, allowing a crafted network packet to trigger an out-of-bounds memory access that crashes the Corosync daemon. This results in a denial of service for the affected cluster node. The overflow does not occur on 64-bit systems, where the length calculation is correctly performed in 64-bit arithmetic.",
  "id": "GHSA-8297-6g53-8gp5",
  "modified": "2026-09-04T12:30:55Z",
  "published": "2026-09-04T12:30:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81666"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-81666"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524923"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

OPENSUSE-SU-2026:11715-1

Vulnerability from csaf_opensuse - Published: 2026-09-08 00:00 - Updated: 2026-09-16 21:29

Summary

corosync-3.1.10-5.1 on GA media

Severity

Moderate

Scope

2 vulnerabilities in this advisory, including CVE-2026-81666.

CVE-2026-81666

6.5 (Medium)


                
                  CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Recommended: 12 products

Open the full advisory

SUSE-SU-2026:4202-1

Vulnerability from csaf_suse - Published: 2026-09-16 08:18 - Updated: 2026-09-17 08:57

Summary

Security update for corosync

Severity

Important

Scope

2 vulnerabilities in this advisory, including CVE-2026-81666.

CVE-2026-81666

6.5 (Medium)


                
                  CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Recommended: 208 products

Open the full advisory

ubuntu-cve-2026-81666

Vulnerability from osv_ubuntu

Published

2026-09-04 10:17

Modified

2026-09-16 11:43

Summary

Details

Severity

6.5 (Medium)


                    
                      CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-81666	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-81666	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "corosync",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "corosync-notifyd",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libcfg6",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libcmap4",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libcorosync-common4",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libcpg4",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libquorum5",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libsam4",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libtotem-pg5",
            "binary_version": "2.3.5-3ubuntu2.3"
          },
          {
            "binary_name": "libvotequorum7",
            "binary_version": "2.3.5-3ubuntu2.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "corosync",
        "purl": "pkg:deb/ubuntu/corosync@2.3.5-3ubuntu2.3?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.4-0ubuntu1",
        "2.3.5-3",
        "2.3.5-3ubuntu1",
        "2.3.5-3ubuntu2",
        "2.3.5-3ubuntu2.1",
        "2.3.5-3ubuntu2.3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "corosync",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "corosync-notifyd",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "corosync-qdevice",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "corosync-qnetd",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libcfg6",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libcmap4",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libcorosync-common4",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libcpg4",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libquorum5",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libsam4",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libtotem-pg5",
            "binary_version": "2.4.3-0ubuntu1.3"
          },
          {
            "binary_name": "libvotequorum8",
            "binary_version": "2.4.3-0ubuntu1.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "corosync",
        "purl": "pkg:deb/ubuntu/corosync@2.4.3-0ubuntu1.3?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.4.2-3build1",
        "2.4.2-3ubuntu1",
        "2.4.3-0ubuntu1",
        "2.4.3-0ubuntu1.1",
        "2.4.3-0ubuntu1.2",
        "2.4.3-0ubuntu1.3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "corosync",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "corosync-notifyd",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "corosync-vqsim",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libcfg7",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libcmap4",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libcorosync-common4",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libcpg4",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libquorum5",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libsam4",
            "binary_version": "3.0.3-2ubuntu2.2"
          },
          {
            "binary_name": "libvotequorum8",
            "binary_version": "3.0.3-2ubuntu2.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "corosync",
        "purl": "pkg:deb/ubuntu/corosync@3.0.3-2ubuntu2.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.1-2ubuntu1",
        "3.0.2-1ubuntu1",
        "3.0.2-1ubuntu2",
        "3.0.3-2ubuntu1",
        "3.0.3-2ubuntu2",
        "3.0.3-2ubuntu2.1",
        "3.0.3-2ubuntu2.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "corosync",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "corosync-notifyd",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "corosync-vqsim",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libcfg7",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libcmap4",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libcorosync-common4",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libcpg4",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libquorum5",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libsam4",
            "binary_version": "3.1.6-1ubuntu1.2"
          },
          {
            "binary_name": "libvotequorum8",
            "binary_version": "3.1.6-1ubuntu1.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "corosync",
        "purl": "pkg:deb/ubuntu/corosync@3.1.6-1ubuntu1.2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.2-2ubuntu1",
        "3.1.6-1ubuntu1",
        "3.1.6-1ubuntu1.1",
        "3.1.6-1ubuntu1.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "corosync",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "corosync-notifyd",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "corosync-vqsim",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libcfg7",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libcmap4",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libcorosync-common4",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libcpg4",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libquorum5",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libsam4",
            "binary_version": "3.1.7-1ubuntu3.2"
          },
          {
            "binary_name": "libvotequorum8",
            "binary_version": "3.1.7-1ubuntu3.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "corosync",
        "purl": "pkg:deb/ubuntu/corosync@3.1.7-1ubuntu3.2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.7-1ubuntu1",
        "3.1.7-1ubuntu2",
        "3.1.7-1ubuntu3",
        "3.1.7-1ubuntu3.1",
        "3.1.7-1ubuntu3.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "corosync",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "corosync-notifyd",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "corosync-vqsim",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libcfg7",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libcmap4",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libcorosync-common4",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libcpg4",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libquorum5",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libsam4",
            "binary_version": "3.1.9-2ubuntu3"
          },
          {
            "binary_name": "libvotequorum8",
            "binary_version": "3.1.9-2ubuntu3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "corosync",
        "purl": "pkg:deb/ubuntu/corosync@3.1.9-2ubuntu3?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.9-2ubuntu1",
        "3.1.9-2ubuntu2",
        "3.1.9-2ubuntu3"
      ]
    }
  ],
  "aliases": [],
  "details": "An integer overflow was found in Corosync\u0027s handling of membership commit token messages. The length-validation check for these messages can be bypassed on 32-bit systems due to an integer overflow in the calculation of the expected message length, allowing a crafted network packet to trigger an out-of-bounds memory access that crashes the Corosync daemon. This results in a denial of service for the affected cluster node. The overflow does not occur on 64-bit systems, where the length calculation is correctly performed in 64-bit arithmetic.",
  "id": "UBUNTU-CVE-2026-81666",
  "modified": "2026-09-16T11:43:09Z",
  "published": "2026-09-04T10:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-81666"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-81666"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-81666"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-81666 (GCVE-0-2026-81666)

FKIE_CVE-2026-81666

GHSA-8297-6G53-8GP5

OPENSUSE-SU-2026:11715-1

SUSE-SU-2026:4202-1

ubuntu-cve-2026-81666

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature

Related by attack behaviour