CVE-2026-81665 (GCVE-0-2026-81665)
Vulnerability from cvelistv5 – Published: 2026-09-04 09:05 – Updated: 2026-09-17 11:43
VLAI
EPSS
VEX
Title
Corosync: corosync: heap-based buffer overflow in totempg assembly buffer during fragmented message reassembly
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.
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-04 17:09 UTC
CWE
- CWE-122 - Heap-based Buffer Overflow
Assigner
References
8 references
| URL | Tags |
|---|---|
| https://access.redhat.com/errata/RHSA-2026:67872 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:67873 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:67878 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:67879 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:67881 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:68574 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/security/cve/CVE-2026-81665 | vdb-entryx_refsource_REDHAT |
| https://bugzilla.redhat.com/show_bug.cgi?id=2524910 | issue-trackingx_refsource_REDHAT |
Impacted products
8 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 |
Unaffected:
0:3.1.10-1.el10_2.2 , < *
(rpm)
cpe:/o:redhat:enterprise_linux:10.2 |
||
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support |
Unaffected:
0:3.1.9-1.el10_0.3 , < *
(rpm)
cpe:/o:redhat:enterprise_linux_eus:10.0 |
||
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support |
Unaffected:
0:2.4.5-7.el7_9.4 , < *
(rpm)
cpe:/o:redhat:enterprise_linux:7::server |
||
| Red Hat | Red Hat Enterprise Linux 9 |
Unaffected:
0:3.1.10-1.el9_8.2 , < *
(rpm)
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 |
||
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions |
Unaffected:
0:3.1.8-1.el9_4.2 , < *
(rpm)
cpe:/a:redhat:rhel_e4s:9.4::appstream cpe:/a:redhat:rhel_e4s:9.4::highavailability cpe:/a:redhat:rhel_e4s:9.4::resilientstorage |
||
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support |
Unaffected:
0:3.1.9-2.el9_6.2 , < *
(rpm)
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 |
||
| Red Hat | Red Hat Enterprise Linux 8 |
cpe:/o:redhat:enterprise_linux:8
|
||
| Red Hat | Red Hat OpenShift Container Platform 4 |
cpe:/a:redhat:openshift:4
|
Date Public
2026-09-04 08:30
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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.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-122\", \"description\": \"Heap-based Buffer Overflow\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-09-16T13:22:53.509Z\"}, \"x_redhatCweChain\": \"CWE-122: Heap-based Buffer Overflow\"}}",
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"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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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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