Read the docs
TI-2021-02681 Aliases CVE-2021-3748GHSA-4f87-mww8-gm8x

Use after free in QEMU

Priority LOW 33CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
High
User interaction
None
Attack complexity
High
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 5 fixed, 5 without a fix

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

Summary

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.

Why it matters now

EPSS 0.00522 44th percentileScored 2026-11-07
Fix Partial Red Hat: 3 advisoriesRed Hat: 5 fixed, 5 without a fix

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
—QEMU (virtio-net)Affects qemu v0.10.0 and above, Fixed In – v6.2.0-rc0 and above.—No fix listedCNA
  • QEMU (virtio-net) Vendor— Affected Affects qemu v0.10.0 and above, Fixed In – v6.2.0-rc0 and above. Fixed in — No fix listed CNA

CPE configurations NVD · 9

CPEVersionsRoleVendor
cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*0.10.0 to before 6.2.0VulnerableQEMU
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:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*18.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*20.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:*21.10VulnerableCanonical
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_advanced_virtualization_eus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
  • cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:* Versions 0.10.0 to before 6.2.0 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
  • cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* Versions 20.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:* Versions 21.10 Vulnerable ·Canonical
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_advanced_virtualization_eus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat

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-2021:5036 Released 2021-12-09 · Red Hat rating Moderate
    virt:8.2 and virt-devel:8.2 security update
    • Advanced Virtualization CodeReady Builder for RHEL 8.2.1 SLOF-20191022-3.git899d9883.module+el8.2.0+5449+efc036dd.src::virt-devel:8.2, hivex-1.3.18-20.module+el8.2.0+5588+63a201c3.i686::virt-devel:8.2, hivex-devel-1.3.18-20.module+el8.2.0+5588+63a201c3.i686::virt-devel:8.2 +47
    • Advanced Virtualization for RHEL 8.2.1 SLOF-20191022-3.git899d9883.module+el8.2.0+5449+efc036dd.noarch::virt:8.2, SLOF-20191022-3.git899d9883.module+el8.2.0+5449+efc036dd.src::virt:8.2, hivex-1.3.18-20.module+el8.2.0+5588+63a201c3.aarch64::virt:8.2 +47
  • RHSA-2021:4112 Released 2021-11-03 · Red Hat rating Moderate
    virt:av and virt-devel:av security and bug fix update
    • Advanced Virtualization for RHEL 8.4.0.Z 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: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 8 Advanced VirtualizationAffectedNo fix yet
Red Hat OpenStack Platform 10 (Newton)AffectedNo fix planned: Out of support scope
Red Hat OpenStack Platform 13 (Queens)AffectedNo fix planned: Out of support scope
Advanced Virtualization CodeReady Builder for RHEL 8.2.1Fixed RHSA-2021:5036
Advanced Virtualization for RHEL 8.2.1Fixed RHSA-2021:5036
Advanced Virtualization for RHEL 8.4.0.ZFixed RHSA-2021:4112
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 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-3748
  2. 2026-10-03 Alias added: GHSA-4f87-mww8-gm8x

References

Patch 4

Advisory 4

Sources

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