Read the docs
TI-2021-02836 Aliases CVE-2021-3929GHSA-h66w-323g-4q62

Use after free in QEMU

Priority LOW 37CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
High
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.

Summary

A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU. This CVE is similar to CVE-2021-3750 and, just like it, when the reentrancy write triggers the reset function nvme_ctrl_reset(), data structs will be freed leading to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition or, potentially, executing arbitrary code within the context of the QEMU process on the host.

Why it matters now

EPSS 0.00678 52nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
—QEMUFixed in qemu-kvm 7.0.0-rc0—No fix listedCNA
  • QEMU Vendor— Affected Fixed in qemu-kvm 7.0.0-rc0 Fixed in — No fix listed CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*before 7.0.0VulnerableQEMU
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*36VulnerableFedoraproject
  • cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:* Versions before 7.0.0 Vulnerable ·QEMU
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

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

Not affected: 7 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 8 Advanced Virtualization
  • Red Hat Enterprise Linux 9
  • Red Hat OpenStack Platform 10 (Newton)
  • Red Hat OpenStack Platform 13 (Queens)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-3929
  2. 2026-10-03 Alias added: GHSA-h66w-323g-4q62

References

Exploit 1

Patch 2

Advisory 3

Sources

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