High
corosync — security advisory
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.
- Products
- corosync
- Affected versions
- 3.1.10-1, 3.1.10-2, 3.1.10-3, 3.1.10-4, 3.1.10-5, 3.1.7-1, 3.1.7-1+deb12u1, 3.1.7-1+deb12u2, 3.1.8-1, 3.1.8-2, 3.1.8-3, 3.1.9-1, 3.1.9-2, 3.1.9-2+deb13u1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-81665
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 02:22 UTC · Revision 1
Source evidence
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.
osv:DEBIAN-CVE-2026-81665
corosync
Fixed versions: Not specified
corosync
Fixed versions: Not specified
corosync
Fixed versions: Not specified
Complete source record
{
"id": "11722fe55ab129f08ffa42bd2fb06d14fcc82968952cb4edceaaa6aa0bdf5b8f",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-81665",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-81665",
"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.",
"evidence": "osv:DEBIAN-CVE-2026-81665",
"products": [
{
"name": {
"value": "corosync",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
"value": "3.1.10-1",
"evidence": "/affected/0/versions"
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{
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{
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{
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{
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{
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{
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{
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{
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{
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}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-81665",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
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"events": [
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"package": {
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"ecosystem": "Debian:12"
},
"versions": [
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"urgency": "not yet assigned"
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{
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"purl": "pkg:deb/debian/corosync?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
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],
"database_specific": {
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},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
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"package": {
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"ecosystem": "Debian:14"
},
"versions": [
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"3.1.10-2",
"3.1.10-3",
"3.1.10-4",
"3.1.10-5",
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],
"database_specific": {
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},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:05:46.410735313Z",
"provider": "osv",
"upstream": [
"CVE-2026-81665"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-81665"
]
},
"related_cves": [
{
"value": "CVE-2026-81665",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 424559,
"published_at": "2026-09-04T09:17:11.357+00:00"
}