CVE-2021-3748 Use after free in QEMU (virtio-net)
High 7.5
Published
Updated
Check this codebase for CVE-2021-3748 and fix it if it is affected.
What it is: CVE-2021-3748 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 23 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3748 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-2021-3748/ (Markdown: https://insights.sbomify.com/CVE-2021-3748/index.md)
A malicious guest can trigger a use-after-free in QEMU's virtio-net device to crash the host or execute arbitrary code with QEMU privileges.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-3748?
CVE-2021-3748 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 23 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.
Weakness: CWE-416
Which versions are affected by CVE-2021-3748?
It affects 6 products.
Linux distribution packages (40)
SLOF Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:20191022-3.git899d9883.module+el8.2.0+5449+efc036dd |
hivex Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.3.18-20.module+el8.2.0+5588+63a201c3 |
hivex-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.3.18-20.module+el8.2.0+5588+63a201c3 |
hivex-debugsource Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.3.18-20.module+el8.2.0+5588+63a201c3 |
hivex-devel Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.3.18-20.module+el8.2.0+5588+63a201c3 |
libguestfs Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-bash-completion Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-benchmarking Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-benchmarking-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-debugsource Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-devel Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-gfs2 Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-gobject Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-gobject-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-gobject-devel Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-inspect-icons Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-java Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-java-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-java-devel Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-javadoc Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-man-pages-ja Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-man-pages-uk Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-rescue Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-rsync Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-tools Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-tools-c Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-tools-c-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libguestfs-winsupport Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:8.2-2.module+el8.2.1+12663+d52ebc0d |
libguestfs-xfs Red Hat:advanced_virtualization:8.2::el8 | All versions | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 |
libiscsi Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.18.0-8.module+el8.2.0+4793+b09dd2fb |
libiscsi-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.18.0-8.module+el8.2.0+4793+b09dd2fb |
libiscsi-debugsource Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.18.0-8.module+el8.2.0+4793+b09dd2fb |
libiscsi-devel Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.18.0-8.module+el8.2.0+4793+b09dd2fb |
libiscsi-utils Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.18.0-8.module+el8.2.0+4793+b09dd2fb |
libiscsi-utils-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.18.0-8.module+el8.2.0+4793+b09dd2fb |
libnbd Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.2.2-1.module+el8.2.0+5644+32ac38d4 |
libnbd-debuginfo Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.2.2-1.module+el8.2.0+5644+32ac38d4 |
libnbd-debugsource Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.2.2-1.module+el8.2.0+5644+32ac38d4 |
libnbd-devel Red Hat:advanced_virtualization:8.2::el8 | All versions | 0:1.2.2-1.module+el8.2.0+5644+32ac38d4 |
Products include Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Qemu Qemu, Redhat Enterprise Linux, Redhat Enterprise Linux Advanced Virtualization Eus.
How do I fix CVE-2021-3748?
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-2021-3748 being exploited?
There is no known exploitation of CVE-2021-3748 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as AZL-9121, DEBIAN-CVE-2021-3748, GHSA-4f87-mww8-gm8x, OESA-2021-1371, RHSA-2021:4112, RHSA-2021:5036 and 1 more.