CVE-2021-3975 Use after free in libvirt
Medium 6.5
Published
Updated
Check this codebase for CVE-2021-3975 and fix it if it is affected.
What it is: CVE-2021-3975 is a medium-severity use after free vulnerability in Canonical Ubuntu Linux, published on 23 Aug 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3975 in the wild and no public exploit code.
Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2021-3975/ (Markdown: https://insights.sbomify.com/CVE-2021-3975/index.md)
An unprivileged client can crash the libvirt daemon via a use-after-free flaw in monitor handling during guest shutdown.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-3975?
CVE-2021-3975 is a medium-severity use after free vulnerability in Canonical Ubuntu Linux, published on 23 Aug 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-416
Which versions are affected by CVE-2021-3975?
It affects 14 products.
Linux distribution packages (40)
SLOF Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:20210217-1.module+el8.5.0+10946+35bb3930 |
hivex Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.3.18-22.module+el8.5.0+12087+2208d04c |
hivex-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.3.18-22.module+el8.5.0+12087+2208d04c |
hivex-debugsource Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.3.18-22.module+el8.5.0+12087+2208d04c |
hivex-devel Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.3.18-22.module+el8.5.0+12087+2208d04c |
libguestfs Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-bash-completion Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-debugsource Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-devel Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-gfs2 Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-gobject Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-gobject-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-gobject-devel Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-inspect-icons Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-java Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-java-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-java-devel Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-javadoc Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-man-pages-ja Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-man-pages-uk Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-rescue Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-rsync Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-tools Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-tools-c Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-tools-c-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libguestfs-winsupport Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:8.2-2.module+el8.5.0+12739+164806c8 |
libguestfs-xfs Red Hat:advanced_virtualization:8.5::el8 | All versions | 1:1.44.0-3.module+el8.5.0+10681+17a9b157 |
libiscsi Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-debugsource Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-devel Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-utils Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-utils-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libnbd Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.6.0-4.module+el8.5.0+11638+3d8f9850 |
libnbd-bash-completion Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.6.0-4.module+el8.5.0+11638+3d8f9850 |
libnbd-debuginfo Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.6.0-4.module+el8.5.0+11638+3d8f9850 |
libnbd-debugsource Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.6.0-4.module+el8.5.0+11638+3d8f9850 |
libnbd-devel Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:1.6.0-4.module+el8.5.0+11638+3d8f9850 |
libtpms Red Hat:advanced_virtualization:8.5::el8 | All versions | 0:0.7.4-6.20201106git2452a24dab.module+el8.5.0+12487+f2fa92b4 |
Products include Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Netapp Ontap Select Deploy Administration Utility, Redhat Codeready Linux Builder, Redhat Enterprise Linux and 8 more.
How do I fix CVE-2021-3975?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2021-3975 being exploited?
There is no known exploitation of CVE-2021-3975 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as CLSA-2022-1654537477, CLSA-2022-1654537694, DEBIAN-CVE-2021-3975, GHSA-pg89-46xq-98vv, OESA-2022-1891, RHBA-2021:4684 and 1 more.