ubuntu-cve-2026-81666
Vulnerability from osv_ubuntu
Published
2026-09-04 10:17
Modified
2026-09-16 11:43
Summary
Details
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)
N/A (UNKNOWN)
References
| URL | Type | |
|---|---|---|
{
"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"
]
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
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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.
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.
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