{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-81666", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-08-27T10:38:28.793Z", "datePublished": "2026-09-04T09:46:06.130Z", "dateUpdated": "2026-09-04T09:46:06.130Z"}, "containers": {"cna": {"title": "Corosync: corosync: integer overflow in check_memb_commit_token_sanity may bypass message length validation on 32-bit systems", "metrics": [{"other": {"content": {"value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "format": "CVSS"}], "descriptions": [{"lang": "en", "value": "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."}], "affected": [{"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "corosync", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:10"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "corosync", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:7"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "corosync", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:8"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "corosync", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:9"]}, {"vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "rhcos", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:openshift:4"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-81666", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524923", "name": "RHBZ#2524923", "tags": ["issue-tracking", "x_refsource_REDHAT"]}], "datePublic": "2026-09-04T08:14:29.525Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-190", "description": "Integer Overflow or Wraparound", "lang": "en", "type": "CWE"}]}], "x_redhatCweChain": "CWE-190: Integer Overflow or Wraparound", "workarounds": [{"lang": "en", "value": "There is no complete mitigation for this vulnerability short of a fix, but the following steps reduce risk:\n\n1. Ensure cluster message authentication is enabled in corosync.conf (crypto_cipher=aes256, crypto_hash=sha256 with a shared key from corosync-keygen), which is the default when clusters are configured via 'pcs cluster setup', 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.\n3. Where architecturally feasible, prefer 64-bit deployments, since the integer overflow described here does not occur on 64-bit systems."}], "timeline": [{"lang": "en", "time": "2026-08-23T00:00:00.000Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-09-04T08:14:29.525Z", "value": "Made public."}], "credits": [{"lang": "en", "value": "Red Hat would like to thank Tristan Madani (Talence Security) for reporting this issue."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-09-04T09:46:06.130Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

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