CVE-2021-3975: Canonical Ubuntu Linux

Medium severity, CVSS 6.5. EPSS: 1.5% chance of exploitation in the next 30 days.

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.

Affected products

• Canonical Ubuntu Linux: version 21.10 only
• Debian Debian Linux: version 10.0 only; version 11.0 only
• Fedoraproject Fedora: version 35 only
• Netapp Ontap Select Deploy Administration Utility: affected versions not specified
• Red Hat Codeready Linux Builder: affected versions not specified
• Red Hat Enterprise Linux: version 8.0 only
• Red Hat Enterprise Linux Eus: version 8.6 only
• Red Hat Enterprise Linux For IBM Z Systems: version 8.0 only
• Red Hat Enterprise Linux For IBM Z Systems Eus: version 8.6 only
• Red Hat Enterprise Linux For Power Little Endian: version 8.0 only
• Red Hat Enterprise Linux For Power Little Endian Eus: version 8.6 only
• Red Hat Enterprise Linux Server For Power Little Endian Update Services For SAP Solutions: version 8.6 only
• Red Hat Enterprise Linux Server Tus: version 8.6 only
• Red Hat Libvirt: before 7.1.0 (fixed in 7.1.0)

Published 2022-08-23. Last modified 2026-06-17.