FKIE_CVE-2026-81665
Vulnerability from fkie_nvd - Published: 2026-09-04 09:17 - Updated: 2026-09-17 12:18
Severity
Summary
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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10.2"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 10",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:3.1.10-1.el10_2.2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux_eus:10.0"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 10.0 Extended Update Support",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:3.1.9-1.el10_0.3",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::server"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 7 Extended Lifecycle Support",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:2.4.5-7.el7_9.4",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"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"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 9",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:3.1.10-1.el9_8.2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"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"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:3.1.8-1.el9_4.2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"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"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 9.6 Extended Update Support",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "0:3.1.9-2.el9_6.2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
],
"defaultStatus": "affected",
"packageName": "corosync",
"product": "Red Hat Enterprise Linux 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openshift/ose-rhel-coreos-9",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "rhcos",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
}
],
"source": "secalert@redhat.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A heap-based buffer overflow was found in Corosync\u0027s 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."
}
],
"id": "CVE-2026-81665",
"lastModified": "2026-09-17T12:18:28.197",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.6,
"impactScore": 5.9,
"source": "secalert@redhat.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-81665",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-04T17:09:13.395902Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-04T09:17:11.357",
"references": [
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:67872"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:67873"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:67878"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:67879"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:67881"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:68574"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/security/cve/CVE-2026-81665"
},
{
"source": "secalert@redhat.com",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524910"
}
],
"sourceIdentifier": "secalert@redhat.com",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-122"
}
],
"source": "secalert@redhat.com",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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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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.
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