CVE-2026-81665 (GCVE-0-2026-81665)
Vulnerability from cvelistv5
Published
2026-09-04 09:05
Modified
2026-10-21 20:43
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-122 - Heap-based Buffer Overflow
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 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Red Hat | Red Hat Enterprise Linux 10 |
Unaffected: 0:3.1.10-1.el10_2.2 < * cpe:/o:redhat:enterprise_linux:10.2 |
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[\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2524910\", \"name\": \"RHBZ#2524910\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"There is no complete mitigation for this vulnerability short of a fix, but the following steps significantly reduce risk:\\n\\n1. Ensure cluster message authentication is enabled in corosync.conf: set crypto_cipher to aes256 and crypto_hash to sha256 (or stronger) in the totem {} block, with a shared key generated by corosync-keygen. This is the default when clusters are configured via \u0027pcs cluster setup\u0027, and disabling it (cipher=none/hash=none) is an explicitly unsupported configuration per upstream maintainer guidance.\\n2. Restrict network access to the cluster communication ports (default 5405-5412/UDP) to trusted cluster node addresses only, using firewalld or other firewall rules.\\n3. Ensure SELinux is running in enforcing mode on cluster nodes to limit the impact of any successful exploitation.\"}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"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.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-122\", \"description\": \"Heap-based Buffer Overflow\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-10-21T20:43:33.349Z\"}, \"x_redhatCweChain\": \"CWE-122: Heap-based Buffer Overflow\"}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-81665\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-21T20:43:33.349Z\", \"dateReserved\": \"2026-08-27T10:38:28.793Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2026-09-04T09:05:35.890Z\", \"assignerShortName\": \"redhat\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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