Description
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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | libvirt | Fixed in libvirt v7.1.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libvirt | 7.6.0-1 | — |
| Debian 13 | libvirt | 7.6.0-1 | — |
| Debian 12 | libvirt | 7.6.0-1 | — |
| Debian 10 | libvirt | 5.0.0-4+deb10u2 | DLA-3778-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | libvirt | 7.6.0-0ubuntu3 | — |
| Ubuntu 20.04 LTS | libvirt | 6.0.0-0ubuntu8.16 | USN-5399-1 |
| Ubuntu 18.04 LTS | libvirt | 4.0.0-1ubuntu8.21 | USN-5399-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | SLOF | 20210217-1.module+el8.5.0+10946+35bb3930 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | hivex +6 | 1.3.18-22.module+el8.5.0+12087+2208d04c | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libguestfs-appliance | 1:1.44.0-5.module+el8.6.0+14480+c0a3aa0f | RHSA-2022:1759 |
| RHEL 8 | libguestfs-winsupport | 8.2-2.module+el8.5.0+12739+164806c8 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libiscsi +2 | 1.18.0-8.module+el8.4.0+8855+a9e237a9 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libnbd +6 | 1.6.0-4.module+el8.5.0+11638+3d8f9850 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libtpms +1 | 0.7.4-6.20201106git2452a24dab.module+el8.5.0+12487+f2fa92b4 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libvirt +27 | 7.6.0-6.module+el8.5.0+13051+7ddbe958 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libvirt-dbus | 1.3.0-2.module+el8.4.0+8855+a9e237a9 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | libvirt-python +1 | 7.6.0-1.module+el8.5.0+12098+85b3670b | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | nbdkit +18 | 1.24.0-1.module+el8.4.0+9341+96cf2672 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | netcf +2 | 0.2.8-12.module+el8.4.0+8855+a9e237a9 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | perl-Sys-Virt | 7.4.0-1.module+el8.5.0+11289+b29e262f | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | python-pyvmomi +1 | 6.7.1-7.module+el8.4.0+8855+a9e237a9 | RHBA-2021:4684 |
| RHEL 8 | qemu-img +15 | 15:6.0.0-33.module+el8.5.0+13041+05be2dc6 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | seabios +2 | 1.14.0-1.module+el8.4.0+8855+a9e237a9 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | sgabios +1 | 1:0.20170427git-3.module+el8.4.0+8855+a9e237a9 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | supermin +1 | 5.2.1-1.module+el8.4.0+9751+d56db353 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | swtpm +4 | 0.6.0-2.20210607gitea627b3.module+el8.5.0+12696+4ce1c6bc | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | virt-dib +23 | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 | RHSA-2022:1759, RHBA-2021:4684 |
| RHEL 8 | virt-v2v +3 | 1:1.42.0-15.module+el8.5.0+12264+1ee0d523 | RHSA-2022:1759, RHBA-2021:4684 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | SLOF | 20210217-1.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | hivex +6 | 1.3.18-23.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | libguestfs-winsupport | 8.6-1.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | libiscsi +2 | 1.18.0-8.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | libnbd +6 | 1.6.0-5.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | libtpms +1 | 0.9.1-0.20211126git1ff6fe1f43.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | libvirt +27 | 8.0.0-5.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | libvirt-dbus | 1.3.0-2.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | nbdkit +18 | 1.24.0-4.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | netcf +2 | 0.2.8-12.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | perl-Sys-Virt +1 | 8.0.0-1.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | qemu-img +14 | 15:6.2.0-11.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | seabios +2 | 1.15.0-2.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | sgabios +1 | 1:0.20170427git-3.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | supermin +1 | 5.2.1-1.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | swtpm +4 | 0.7.0-1.20211109gitb79fd91.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
| AlmaLinux 8 | virt-dib +24 | 1:1.44.0-5.module_el8.6.0+2880+7d9e3703.alma | ALSA-2022:1759 |
| AlmaLinux 8 | virt-v2v +3 | 1:1.42.0-18.module_el8.6.0+2880+7d9e3703 | ALSA-2022:1759 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | hivex | 1.3.18-23.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | libguestfs | 1:1.44.0-5.module+el8.6.0+1052+ff61d164.rocky | RLSA-2022:1759 |
| Rocky Linux 8 | libguestfs-winsupport | 8.6-1.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | libiscsi | 1.18.0-8.module+el8.4.0+534+4680a14e | RLSA-2022:1759 |
| Rocky Linux 8 | libnbd | 1.6.0-5.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | libtpms | 0.9.1-0.20211126git1ff6fe1f43.module+el8.6.0+1052+ff61d164 | RLSA-2022:1759 |
| Rocky Linux 8 | libvirt | 8.0.0-5.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | libvirt-dbus | 1.3.0-2.module+el8.4.0+534+4680a14e | RLSA-2022:1759 |
| Rocky Linux 8 | nbdkit | 1.24.0-4.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | netcf | 0.2.8-12.module+el8.4.0+534+4680a14e | RLSA-2022:1759 |
| Rocky Linux 8 | perl-Sys-Virt +1 | 8.0.0-1.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | qemu-kvm | 5:6.2.0-11.module+el8.6.0+1000+18e3b59f.5 | RLSA-2022:1759 |
| Rocky Linux 8 | seabios | 1.15.0-2.module+el8.6.0+1052+ff61d164 | RLSA-2022:1759 |
| Rocky Linux 8 | sgabios | 1:0.20170427git-3.module+el8.4.0+534+4680a14e | RLSA-2022:1759 |
| Rocky Linux 8 | supermin | 5.2.1-1.module+el8.6.0+1052+ff61d164 | RLSA-2022:1759 |
| Rocky Linux 8 | swtpm | 0.7.0-1.20211109gitb79fd91.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
| Rocky Linux 8 | virt-v2v | 1:1.42.0-18.module+el8.6.0+847+b490afdd | RLSA-2022:1759 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SLES 15 SP1 | libvirt | 5.1.0-17.1 | SUSE-SU-2022:0128-1 |
| SLES 15 | libvirt | 4.0.0-9.40.1 | SUSE-SU-2022:0031-1 |
| SLES 12 SP5 | libvirt | 5.1.0-13.28.2 | SUSE-SU-2022:0032-1 |
| SLES 12 SP4 | libvirt | 4.0.0-8.26.1 | SUSE-SU-2022:0042-1 |
Show 22 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | libvirt | 3.3.0-5.49.1 | SUSE-SU-2022:0041-1 |
| SLES for SAP 15 SP2 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SLES for SAP 15 SP1 | libvirt | 5.1.0-17.1 | SUSE-SU-2022:0128-1 |
| SLES for SAP 15 | libvirt | 4.0.0-9.40.1 | SUSE-SU-2022:0031-1 |
| SLES for SAP 12 SP5 | libvirt | 5.1.0-13.28.2 | SUSE-SU-2022:0032-1 |
| SLES for SAP 12 SP4 | libvirt | 4.0.0-8.26.1 | SUSE-SU-2022:0042-1 |
| SLES for SAP 12 SP3 | libvirt | 3.3.0-5.49.1 | SUSE-SU-2022:0041-1 |
| SLE Real Time 15 SP2 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-2 |
| SLE Micro 5.0 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SLE HPC 15 SP2 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SLE HPC 15 SP1 | libvirt | 5.1.0-17.1 | SUSE-SU-2022:0128-1 |
| SLE HPC 15 | libvirt | 4.0.0-9.40.1 | SUSE-SU-2022:0031-1 |
| SUSE OpenStack Cloud Crowbar 9 | libvirt | 4.0.0-8.26.1 | SUSE-SU-2022:0042-1 |
| SUSE OpenStack Cloud Crowbar 8 | libvirt | 3.3.0-5.49.1 | SUSE-SU-2022:0041-1 |
| SUSE OpenStack Cloud 9 | libvirt | 4.0.0-8.26.1 | SUSE-SU-2022:0042-1 |
| SUSE OpenStack Cloud 8 | libvirt | 3.3.0-5.49.1 | SUSE-SU-2022:0041-1 |
| SUSE Manager Server 4.1 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SUSE Manager Retail Branch Server 4.1 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SUSE Manager Proxy 4.1 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SUSE HPE Helion OpenStack 8 | libvirt | 3.3.0-5.49.1 | SUSE-SU-2022:0041-1 |
| SUSE Enterprise Storage 7 | libvirt | 6.0.0-13.24.1 | SUSE-SU-2022:0045-1 |
| SUSE Enterprise Storage 6 | libvirt | 5.1.0-17.1 | SUSE-SU-2022:0128-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | hivex +4 | 1.3.18-21.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | libguestfs-winsupport | 8.2-1.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | libiscsi +2 | 1.18.0-8.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | libnbd +3 | 1.2.2-1.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | libtpms +1 | 0.9.1-0.20211126git1ff6fe1f43.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | libvirt +29 | 5.7.0-34.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | libvirt-dbus | 1.3.0-2.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | libvirt-wireshark | 8.0.0-5.0.1.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | nbdkit +13 | 1.16.2-4.0.1.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | nbdkit-nbd-plugin +4 | 1.24.0-4.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | netcf +2 | 0.2.8-12.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | ocaml-hivex +1 | 1.3.18-23.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | ocaml-libguestfs +2 | 1:1.44.0-5.0.1.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | ocaml-libnbd +2 | 1.6.0-5.module+el8.6.0+20664+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | perl-Sys-Virt | 4.5.0-5.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | qemu-img +9 | 15:4.2.1-18.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | qemu-kvm-docs +4 | 15:6.2.0-11.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | seabios +2 | 1.13.0-2.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | sgabios +1 | 1:0.20170427git-3.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | supermin +1 | 5.1.19-10.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | swtpm +4 | 0.7.0-1.20211109gitb79fd91.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 8 | virt-dib +23 | 1:1.40.2-28.0.4.module+el8.6.0+20690+93de6acb | ELSA-2022-9700, ELSA-2022-1759 |
| Oracle Linux 8 | virt-v2v-man-pages-ja +2 | 1:1.42.0-18.0.1.module+el8.6.0+20659+3dcf7c70 | ELSA-2022-1759 |
| Oracle Linux 7 | libvirt +32 | 5.7.0-34.el7 | ELSA-2022-9668 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
yan5ui/ENV-CVE-2021-3975 ★ 0 · Jun 17, 2026
Aritifacts of docker env of CVE-2021-3975
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 17
- ALSA-2022:1759 Moderate: virt:rhel and virt-devel:rhel security, bug fix, and enhancement update AlmaLinux Security Advisories · Oct 31, 2026
- RHSA-2022:1759 Red Hat Security Advisory: virt:rhel and virt-devel:rhel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jul 5, 2026
- RHBA-2021:4684 Red Hat Bug Fix Advisory: virt:av bug fix and enhancement update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- USN-5399-1 libvirt vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DLA-3778-1 libvirt - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2022:1759 Moderate: virt:rhel and virt-devel:rhel security, bug fix, and enhancement update Rocky Linux Security Advisories · Feb 4, 2026
- SUSE-SU-2022:0042-1 Security update for libvirt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0032-1 Security update for libvirt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0128-1 Security update for libvirt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0041-1 Security update for libvirt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0045-2 Security update for libvirt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0031-1 Security update for libvirt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0045-1 Security update for libvirt SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2022-0885 libvirt: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Apr 1, 2024
- ELSA-2022-9700 Important: virt:kvm_utils security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Aug 8, 2022
- ELSA-2022-9668 Important: libvirt libvirt-python security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Aug 1, 2022
- ELSA-2022-1759 Moderate: virt:ol and virt-devel:ol security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 17, 2022
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2024326
- https://access.redhat.com/security/cve/CVE-2021-3975
- https://ubuntu.com/security/CVE-2021-3975
- https://github.com/libvirt/libvirt/commit/1ac703a7d0789e46833f4013a3876c2e3af18ec7
- https://security.netapp.com/advisory/ntap-20221201-0002/
- [debian-lts-announce] 20240401 [SECURITY] [DLA 3778-1] libvirt security update mailing-list