{"id":"UBUNTU-CVE-2026-81666","details":"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.","modified":"2026-09-16T11:43:09Z","published":"2026-09-04T10:17:00Z","upstream":["CVE-2026-81666"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-81666"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-81666"}],"affected":[{"package":{"name":"corosync","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/corosync?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.4-0ubuntu1","2.3.5-3","2.3.5-3ubuntu1","2.3.5-3ubuntu2","2.3.5-3ubuntu2.1","2.3.5-3ubuntu2.3"],"ecosystem_specific":{"binaries":[{"binary_name":"corosync","binary_version":"2.3.5-3ubuntu2.3"},{"binary_name":"corosync-notifyd","binary_version":"2.3.5-3ubuntu2.3"},{"binary_name":"libcfg6","binary_version":"2.3.5-3ubuntu2.3"},{"binary_name":"libcmap4","binary_version":"2.3.5-3ubuntu2.3"},{"binary_name":"libcorosync-common4","binary_version":"2.3.5-3ubuntu2.3"},{"binary_name":"libcpg4","binary_version":"2.3.5-3ubuntu2.3"},{"binary_version":"2.3.5-3ubuntu2.3","binary_name":"libquorum5"},{"binary_name":"libsam4","binary_version":"2.3.5-3ubuntu2.3"},{"binary_name":"libtotem-pg5","binary_version":"2.3.5-3ubuntu2.3"},{"binary_version":"2.3.5-3ubuntu2.3","binary_name":"libvotequorum7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-81666.json"}},{"package":{"name":"corosync","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/corosync?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.2-3build1","2.4.2-3ubuntu1","2.4.3-0ubuntu1","2.4.3-0ubuntu1.1","2.4.3-0ubuntu1.2","2.4.3-0ubuntu1.3"],"ecosystem_specific":{"binaries":[{"binary_version":"2.4.3-0ubuntu1.3","binary_name":"corosync"},{"binary_version":"2.4.3-0ubuntu1.3","binary_name":"corosync-notifyd"},{"binary_name":"corosync-qdevice","binary_version":"2.4.3-0ubuntu1.3"},{"binary_name":"corosync-qnetd","binary_version":"2.4.3-0ubuntu1.3"},{"binary_name":"libcfg6","binary_version":"2.4.3-0ubuntu1.3"},{"binary_name":"libcmap4","binary_version":"2.4.3-0ubuntu1.3"},{"binary_name":"libcorosync-common4","binary_version":"2.4.3-0ubuntu1.3"},{"binary_version":"2.4.3-0ubuntu1.3","binary_name":"libcpg4"},{"binary_version":"2.4.3-0ubuntu1.3","binary_name":"libquorum5"},{"binary_version":"2.4.3-0ubuntu1.3","binary_name":"libsam4"},{"binary_name":"libtotem-pg5","binary_version":"2.4.3-0ubuntu1.3"},{"binary_name":"libvotequorum8","binary_version":"2.4.3-0ubuntu1.3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-81666.json"}},{"package":{"name":"corosync","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/corosync?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.0.1-2ubuntu1","3.0.2-1ubuntu1","3.0.2-1ubuntu2","3.0.3-2ubuntu1","3.0.3-2ubuntu2","3.0.3-2ubuntu2.1","3.0.3-2ubuntu2.2"],"ecosystem_specific":{"binaries":[{"binary_name":"corosync","binary_version":"3.0.3-2ubuntu2.2"},{"binary_name":"corosync-notifyd","binary_version":"3.0.3-2ubuntu2.2"},{"binary_name":"corosync-vqsim","binary_version":"3.0.3-2ubuntu2.2"},{"binary_name":"libcfg7","binary_version":"3.0.3-2ubuntu2.2"},{"binary_version":"3.0.3-2ubuntu2.2","binary_name":"libcmap4"},{"binary_name":"libcorosync-common4","binary_version":"3.0.3-2ubuntu2.2"},{"binary_version":"3.0.3-2ubuntu2.2","binary_name":"libcpg4"},{"binary_name":"libquorum5","binary_version":"3.0.3-2ubuntu2.2"},{"binary_name":"libsam4","binary_version":"3.0.3-2ubuntu2.2"},{"binary_name":"libvotequorum8","binary_version":"3.0.3-2ubuntu2.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-81666.json"}},{"package":{"name":"corosync","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/corosync?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-2ubuntu1","3.1.6-1ubuntu1","3.1.6-1ubuntu1.1","3.1.6-1ubuntu1.2"],"ecosystem_specific":{"binaries":[{"binary_name":"corosync","binary_version":"3.1.6-1ubuntu1.2"},{"binary_version":"3.1.6-1ubuntu1.2","binary_name":"corosync-notifyd"},{"binary_name":"corosync-vqsim","binary_version":"3.1.6-1ubuntu1.2"},{"binary_name":"libcfg7","binary_version":"3.1.6-1ubuntu1.2"},{"binary_name":"libcmap4","binary_version":"3.1.6-1ubuntu1.2"},{"binary_version":"3.1.6-1ubuntu1.2","binary_name":"libcorosync-common4"},{"binary_name":"libcpg4","binary_version":"3.1.6-1ubuntu1.2"},{"binary_name":"libquorum5","binary_version":"3.1.6-1ubuntu1.2"},{"binary_name":"libsam4","binary_version":"3.1.6-1ubuntu1.2"},{"binary_version":"3.1.6-1ubuntu1.2","binary_name":"libvotequorum8"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-81666.json"}},{"package":{"name":"corosync","ecosystem":"Ubuntu:24.04:LTS","purl"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