CVE-2021-3975

Publication date 24 November 2021

Last updated 18 August 2025

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

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.

Status

Package Ubuntu Release Status
libvirt 25.10 questing
Fixed 7.6.0-0ubuntu3
25.04 plucky
Fixed 7.6.0-0ubuntu3
24.10 oracular
Fixed 7.6.0-0ubuntu3
24.04 LTS noble
Fixed 7.6.0-0ubuntu3
23.10 mantic
Fixed 7.6.0-0ubuntu3
23.04 lunar
Fixed 7.6.0-0ubuntu3
22.10 kinetic
Fixed 7.6.0-0ubuntu3
22.04 LTS jammy
Fixed 7.6.0-0ubuntu3
21.10 impish
Not affected
21.04 hirsute Ignored end of life
20.04 LTS focal
Fixed 6.0.0-0ubuntu8.16
18.04 LTS bionic
Fixed 4.0.0-1ubuntu8.21
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
libvirt

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

Other references