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TI-2021-03494 Aliases CVE-2021-20196GHSA-ggpp-fxg5-wp87

NULL pointer dereference in qemu

Priority LOW 29CWE-476Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 4 fixed, 6 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-476.

Summary

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.

Why it matters now

EPSS 0.00479 41st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 3 advisoriesRed Hat: 4 fixed, 6 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—qemuvulnerable up to (including) qemu 5.2.0—No fix listedCNA
  • qemu Vendor— Affected vulnerable up to (including) qemu 5.2.0 Fixed in — No fix listed CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:qemu:qemu:5.2.0:-:*:*:*:*:*:*5.2.0VulnerableQEMU
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
  • cpe:2.3:a:qemu:qemu:5.2.0:-:*:*:*:*:*:* Versions 5.2.0 Vulnerable ·QEMU
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian

Remediation

Red Hat 3 advisories

  • RHSA-2022:1759 Released 2022-05-10 · Red Hat rating Moderate
    virt:rhel and virt-devel:rhel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 8) SLOF-20210217-1.module+el8.6.0+14480+c0a3aa0f.noarch::virt:rhel, SLOF-20210217-1.module+el8.6.0+14480+c0a3aa0f.src::virt:rhel, hivex-1.3.18-23.module+el8.6.0+14480+c0a3aa0f.aarch64::virt:rhel +47
    • Red Hat Enterprise Linux CRB (v. 8) SLOF-20210217-1.module+el8.6.0+14480+c0a3aa0f.src::virt-devel:rhel, hivex-1.3.18-23.module+el8.6.0+14480+c0a3aa0f.i686::virt-devel:rhel, hivex-devel-1.3.18-23.module+el8.6.0+14480+c0a3aa0f.i686::virt-devel:rhel +47
  • RHSA-2022:0397 Released 2022-02-02 · Red Hat rating Low
    virt:av and virt-devel:av security and bug fix update
    • Advanced Virtualization for RHEL 8.5.0.Z SLOF-20210217-1.module+el8.5.0+10946+35bb3930.noarch::virt:av, SLOF-20210217-1.module+el8.5.0+10946+35bb3930.src::virt-devel:av, SLOF-20210217-1.module+el8.5.0+10946+35bb3930.src::virt:av +47
  • RHSA-2022:0325 Released 2022-01-31 · Red Hat rating Low
    virt:av and virt-devel:av security and bug fix update
    • Advanced Virtualization for RHEL 8.4.0.EUS SLOF-20200717-1.gite18ddad8.module+el8.4.0+8855+a9e237a9.noarch::virt:av, SLOF-20200717-1.gite18ddad8.module+el8.4.0+8855+a9e237a9.src::virt-devel:av, SLOF-20200717-1.gite18ddad8.module+el8.4.0+8855+a9e237a9.src::virt:av +47

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 5AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8 Advanced VirtualizationAffectedNo fix yet
Red Hat OpenStack Platform 10 (Newton)AffectedNo fix planned: Will not fix
Red Hat OpenStack Platform 13 (Queens)AffectedNo fix planned: Will not fix
Advanced Virtualization for RHEL 8.4.0.EUSFixed RHSA-2022:0325
Advanced Virtualization for RHEL 8.5.0.ZFixed RHSA-2022:0397
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2022:1759
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2022:1759
Not affected: 1 product
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-20196
  2. 2026-10-03 Alias added: GHSA-ggpp-fxg5-wp87

References

Exploit 1

Patch 1

Advisory 3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences