{"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":"2026-10-21T20:06:18.061Z"},"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":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]},{"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":"2026-10-21T20:06:18.061Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T14:41:30.256254Z","id":"CVE-2026-81666","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-08T14:41:40.015Z"}}]}}