{"id":"UBUNTU-CVE-2021-3975","details":"A use-after-free flaw was found in libvirt. The qemuMonitorUnregister() function in qemuProcessHandleMonitorEOF is called using multiple threads without being adequately protected by a monitor lock. This flaw could be triggered by the virConnectGetAllDomainStats API when the guest is shutting down. An unprivileged client with a read-only connection could use this flaw to perform a denial of service attack by causing the libvirt daemon to crash.","modified":"2026-08-15T01:45:04.555291151Z","published":"2021-11-24T00:00:00Z","related":["USN-5399-1"],"upstream":["CVE-2021-3975"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-3975"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5399-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-3975"}],"affected":[{"package":{"name":"libvirt","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libvirt?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.0.0-1ubuntu8.21"}]}],"versions":["3.6.0-1ubuntu5","3.6.0-1ubuntu6","4.0.0-1ubuntu1","4.0.0-1ubuntu2","4.0.0-1ubuntu3","4.0.0-1ubuntu4","4.0.0-1ubuntu5","4.0.0-1ubuntu6","4.0.0-1ubuntu7","4.0.0-1ubuntu8","4.0.0-1ubuntu8.1","4.0.0-1ubuntu8.2","4.0.0-1ubuntu8.3","4.0.0-1ubuntu8.4","4.0.0-1ubuntu8.5","4.0.0-1ubuntu8.6","4.0.0-1ubuntu8.7","4.0.0-1ubuntu8.8","4.0.0-1ubuntu8.9","4.0.0-1ubuntu8.10","4.0.0-1ubuntu8.11","4.0.0-1ubuntu8.12","4.0.0-1ubuntu8.13","4.0.0-1ubuntu8.14","4.0.0-1ubuntu8.15","4.0.0-1ubuntu8.16","4.0.0-1ubuntu8.17","4.0.0-1ubuntu8.19","4.0.0-1ubuntu8.20"],"ecosystem_specific":{"binaries":[{"binary_name":"libnss-libvirt","binary_version":"4.0.0-1ubuntu8.21"},{"binary_name":"libvirt-bin","binary_version":"4.0.0-1ubuntu8.21"},{"binary_version":"4.0.0-1ubuntu8.21","binary_name":"libvirt-clients"},{"binary_name":"libvirt-daemon","binary_version":"4.0.0-1ubuntu8.21"},{"binary_name":"libvirt-daemon-driver-storage-gluster","binary_version":"4.0.0-1ubuntu8.21"},{"binary_version":"4.0.0-1ubuntu8.21","binary_name":"libvirt-daemon-driver-storage-rbd"},{"binary_version":"4.0.0-1ubuntu8.21","binary_name":"libvirt-daemon-driver-storage-sheepdog"},{"binary_name":"libvirt-daemon-driver-storage-zfs","binary_version":"4.0.0-1ubuntu8.21"},{"binary_version":"4.0.0-1ubuntu8.21","binary_name":"libvirt-daemon-system"},{"binary_name":"libvirt-sanlock","binary_version":"4.0.0-1ubuntu8.21"},{"binary_version":"4.0.0-1ubuntu8.21","binary_name":"libvirt-wireshark"},{"binary_version":"4.0.0-1ubuntu8.21","binary_name":"libvirt0"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3975.json"}},{"package":{"name":"libvirt","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libvirt?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.0.0-0ubuntu8.16"}]}],"versions":["5.4.0-0ubuntu5","6.0.0-0ubuntu1","6.0.0-0ubuntu2","6.0.0-0ubuntu3","6.0.0-0ubuntu4","6.0.0-0ubuntu5","6.0.0-0ubuntu6","6.0.0-0ubuntu7","6.0.0-0ubuntu8","6.0.0-0ubuntu8.1","6.0.0-0ubuntu8.2","6.0.0-0ubuntu8.3","6.0.0-0ubuntu8.4","6.0.0-0ubuntu8.5","6.0.0-0ubuntu8.7","6.0.0-0ubuntu8.8","6.0.0-0ubuntu8.9","6.0.0-0ubuntu8.10","6.0.0-0ubuntu8.11","6.0.0-0ubuntu8.12","6.0.0-0ubuntu8.13","6.0.0-0ubuntu8.14","6.0.0-0ubuntu8.15"],"ecosystem_specific":{"binaries":[{"binary_name":"libnss-libvirt","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-clients","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-driver-lxc","binary_version":"6.0.0-0ubuntu8.16"},{"binary_version":"6.0.0-0ubuntu8.16","binary_name":"libvirt-daemon-driver-qemu"},{"binary_name":"libvirt-daemon-driver-storage-gluster","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-driver-storage-rbd","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-driver-storage-zfs","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-driver-vbox","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-driver-xen","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-system","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-system-systemd","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-daemon-system-sysv","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-sanlock","binary_version":"6.0.0-0ubuntu8.16"},{"binary_name":"libvirt-wireshark","binary_version":"6.0.0-0ubuntu8.16"},{"binary_version":"6.0.0-0ubuntu8.16","binary_name":"libvirt0"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3975.json"}},{"package":{"name":"libvirt","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libvirt?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.6.0-0ubuntu3"}]}],"versions":["7.6.0-0ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnss-libvirt","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-clients"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon"},{"binary_name":"libvirt-daemon-config-network","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-config-nwfilter"},{"binary_name":"libvirt-daemon-driver-lxc","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-driver-qemu"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-driver-storage-gluster"},{"binary_name":"libvirt-daemon-driver-storage-iscsi-direct","binary_version":"7.6.0-0ubuntu3"},{"binary_name":"libvirt-daemon-driver-storage-rbd","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-driver-storage-zfs"},{"binary_name":"libvirt-daemon-driver-vbox","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-driver-xen"},{"binary_name":"libvirt-daemon-system","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-system-systemd"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-daemon-system-sysv"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt-login-shell"},{"binary_name":"libvirt-sanlock","binary_version":"7.6.0-0ubuntu3"},{"binary_name":"libvirt-wireshark","binary_version":"7.6.0-0ubuntu3"},{"binary_version":"7.6.0-0ubuntu3","binary_name":"libvirt0"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3975.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"low"}]}