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.
総合評価: CVE-2021-3975 は中リスク（48.7/100）。CVSS 深刻度は中。悪用される可能性が高い（EPSS 1.17%、63 パーセンタイル） 推奨対応: 影響資産を整理し、修補計画に組み込んでください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.61% | 1.17% | +0.56% |
| 2 | 2026-05-29 | 0.46% | 0.61% | +0.16% |
| 3 | 2026-01-30 | — | 0.46% | — |
EPSS の全履歴 （全 17 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2021-3975: 1 source package rows (libvirt); 6 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 6. | https://security.alpinelinux.org/vuln/CVE-2021-3975 |
debian
|
not yet assigned | CVE-2021-3975 not yet assigned priority: Debian including 1 source packages (libvirt), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2021-3975 |
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2021-3975 |
suse
|
medium | CVE-2021-3975 severity moderate: SUSE including 452 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 1841 product×package rows across 72 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-SAP-BYOS, … (72 product lines)): Fixed 1184, Known Not Affected 426, Known Affected 231. | https://www.suse.com/security/cve/CVE-2021-3975/ |
ubuntu
|
low | CVE-2021-3975 low priority: Ubuntu including 1 source packages (libvirt), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): released 11, needs-triage 2, ignored 1, not-affected 1. | https://ubuntu.com/security/CVE-2021-3975 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| redhat | libvirt | < 7.1.0 | cpe:2.3:a:redhat:libvirt:*:*:*:*:*:*:*:* |
| canonical | ubuntu_linux | 21.10 | cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:* |
| fedoraproject | fedora | 35 | cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* |
| redhat | enterprise_linux | 8.0 | cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_eus | 8.6 | cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_for_ibm_z_systems | 8.0 | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_for_ibm_z_systems_eus | 8.6 | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_for_power_little_endian | 8.0 | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_for_power_little_endian_eus | 8.6 | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions | 8.6 | cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server_tus | 8.6 | cpe:2.3:o:redhat:enterprise_linux_server_tus:8.6:*:*:*:*:*:*:* |
| redhat | codeready_linux_builder | — | cpe:2.3:a:redhat:codeready_linux_builder:-:*:*:*:*:*:*:* |
| debian | debian_linux | 10.0 | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
| debian | debian_linux | 11.0 | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* |
| netapp | ontap_select_deploy_administration_utility | — | cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:* |
| URL | タグ |
|---|---|
| https://access.redhat.com/security/cve/CVE-2021-3975 | Issue Tracking Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2024326 | Issue Tracking Patch Third Party Advisory |
| https://github.com/libvirt/libvirt/commit/1ac703a7d0789e46833f4013a3876c2e3af18ec7 | Patch Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2024/04/msg00000.html | |
| https://security.netapp.com/advisory/ntap-20221201-0002/ | Third Party Advisory |
| https://ubuntu.com/security/CVE-2021-3975 | Patch Third Party Advisory |