Out-of-bounds read in qemu
Priority LOW 27CWE-125Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 6 fixed, 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-125 and the CVSS impact.
Summary
An out-of-bounds heap buffer access issue was found in the ARM Generic Interrupt Controller emulator of QEMU up to and including qemu 4.2.0on aarch64 platform. The issue occurs because while writing an interrupt ID to the controller memory area, it is not masked to be 4 bits wide. It may lead to the said issue while updating controller state fields and their subsequent processing. A privileged guest user may use this flaw to crash the QEMU process on the host resulting in DoS scenario.
Why it matters now
EPSS 0.00326 25th percentileScored 2026-11-07
Fix Partial Red Hat: 3 advisoriesRed Hat: 6 fixed, 4 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | qemu | up to, including qemu 4.2.0 | — | No fix listed | CNA |
- qemu Vendor— Affected up to, including qemu 4.2.0 Fixed in — No fix listed CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:arm64:* | up to 4.2.0 | Vulnerable | QEMU |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:-:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
- cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:arm64:* Versions up to 4.2.0 Vulnerable ·QEMU
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:-:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:* Versions 8.0 Vulnerable ·Red Hat
- 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-2021:3061 Released 2021-08-10 · Red Hat rating Moderatevirt:rhel and virt-devel:rhel security and bug fix update
- Red Hat CodeReady Linux Builder (v. 8) SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.src::virt-devel:rhel, hivex-1.3.18-21.module+el8.4.0+10770+19c037f9.i686::virt-devel:rhel, hivex-devel-1.3.18-21.module+el8.4.0+10770+19c037f9.i686::virt-devel:rhel +47
- Red Hat Enterprise Linux AppStream (v. 8) SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.noarch::virt:rhel, SLOF-20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418.src::virt:rhel, hivex-1.3.18-21.module+el8.4.0+10770+19c037f9.aarch64::virt:rhel +47
- RHSA-2021:2521 Released 2021-06-22 · Red Hat rating Moderatevirt: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-2021:1125 Released 2021-04-08 · Red Hat rating Lowvirt:8.3 and virt-devel:8.3 security and bug fix update
- Advanced Virtualization CodeReady Builder for RHEL 8.3.1 SLOF-20200717-1.gite18ddad8.module+el8.3.0+7638+07cf13d2.src::virt-devel:8.3, hivex-1.3.18-20.module+el8.3.0+6124+819ee737.i686::virt-devel:8.3, hivex-devel-1.3.18-20.module+el8.3.0+6124+819ee737.i686::virt-devel:8.3 +47
- Advanced Virtualization for RHEL 8.3.1 SLOF-20200717-1.gite18ddad8.module+el8.3.0+7638+07cf13d2.noarch::virt:8.3, SLOF-20200717-1.gite18ddad8.module+el8.3.0+7638+07cf13d2.src::virt:8.3, hivex-1.3.18-20.module+el8.3.0+6124+819ee737.aarch64::virt:8.3 +47
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 Advanced Virtualization | Affected | No fix yet |
| Red Hat OpenStack Platform 10 (Newton) | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 13 (Queens) | Affected | No fix planned: Out of support scope |
| Advanced Virtualization CodeReady Builder for RHEL 8.2.1 | Fixed | RHSA-2021:2521 |
| Advanced Virtualization CodeReady Builder for RHEL 8.3.1 | Fixed | RHSA-2021:1125 |
| Advanced Virtualization for RHEL 8.2.1 | Fixed | RHSA-2021:2521 |
| Advanced Virtualization for RHEL 8.3.1 | Fixed | RHSA-2021:1125 |
| Red Hat CodeReady Linux Builder (v. 8) | Fixed | RHSA-2021:3061 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2021:3061 |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2021-20221
- 2026-10-03 Alias added: GHSA-3f6w-864h-4prm
References
Patch 2
Sources
- CVE-2021-20221 · CVE Program
- CVE-2021-20221 · NVD
- FIRST EPSS
- GHSA-3f6w-864h-4prm · GitHub Advisory Database · CC BY 4.0
- CVE-2021-20221 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences