CVE-2021-20196 Null dereference in qemu
Medium 6.5
Published
Updated
Check this codebase for CVE-2021-20196 and fix it if it is affected.
What it is: CVE-2021-20196 is a medium-severity vulnerability in Debian Debian Linux, published on 26 May 2021. 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-2021-20196 in the wild and no public exploit code.
Affected product: Debian Debian 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-2021-20196/ (Markdown: https://insights.sbomify.com/CVE-2021-20196/index.md)
A privileged guest user can crash the QEMU host process via a null pointer dereference in the floppy disk emulator, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-20196?
CVE-2021-20196 is a medium-severity vulnerability in Debian Debian Linux, published on 26 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
Weakness: CWE-476
Which versions are affected by CVE-2021-20196?
It affects 2 products.
Linux distribution packages (40)
SLOF Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:20200717-1.gite18ddad8.module+el8.4.0+8855+a9e237a9 |
hivex Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.3.18-21.module+el8.4.0+11609+2eba841a |
hivex-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.3.18-21.module+el8.4.0+11609+2eba841a |
hivex-debugsource Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.3.18-21.module+el8.4.0+11609+2eba841a |
hivex-devel Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.3.18-21.module+el8.4.0+11609+2eba841a |
libguestfs Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-bash-completion Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-debugsource Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-devel Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-gfs2 Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-gobject Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-gobject-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-gobject-devel Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-inspect-icons Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-java Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-java-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-java-devel Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-javadoc Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-man-pages-ja Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-man-pages-uk Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-rescue Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-rsync Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-tools Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-tools-c Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-tools-c-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libguestfs-winsupport Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:8.2-2.module+el8.4.0+12717+0b0da9ad |
libguestfs-xfs Red Hat:advanced_virtualization:8.4::el8 | All versions | 1:1.44.0-2.module+el8.4.0+10146+75917d2f |
libiscsi Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-debugsource Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-devel Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-utils Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libiscsi-utils-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.18.0-8.module+el8.4.0+8855+a9e237a9 |
libnbd Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.6.0-3.module+el8.4.0+9856+bbc47853 |
libnbd-bash-completion Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.6.0-3.module+el8.4.0+9856+bbc47853 |
libnbd-debuginfo Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.6.0-3.module+el8.4.0+9856+bbc47853 |
libnbd-debugsource Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.6.0-3.module+el8.4.0+9856+bbc47853 |
libnbd-devel Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:1.6.0-3.module+el8.4.0+9856+bbc47853 |
libtpms Red Hat:advanced_virtualization:8.4::el8 | All versions | 0:0.7.4-4.20201106git2452a24dab.module+el8.4.0+10596+32ba7df3 |
Products include Debian Debian Linux, Qemu Qemu.
How do I fix CVE-2021-20196?
Apply the vendor's patch.
Is CVE-2021-20196 being exploited?
There is no known exploitation of CVE-2021-20196 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2021-20196, GHSA-ggpp-fxg5-wp87, RHSA-2022:0325, SUSE-SU-2022:0177-1, UBUNTU-CVE-2021-20196, openSUSE-SU-2022:0177-1.