Is CVE-2021-20221 in the CISA KEV catalog?

No. CVE-2021-20221 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-20221?

CVE-2021-20221 has a CVSS v3 base score of 6.0 (MEDIUM).

What is the EPSS score for CVE-2021-20221?

CVE-2021-20221 has an EPSS score of 0.32% (24th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-20221?

Upgrade qemu on debian 11 to 1:5.2+dfsg-4 or later. Fixes are available for 25 affected products.

CVE & CISA-KEV Catalog

CVE-2021-20221

MEDIUM

6.0

CVSS v3

NVD

Description

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.

CWE-125Out-of-bounds Read CWE-787Out-of-bounds Write

How to fix

Remediation Available

qemuDebian

Fixed in:1:5.2+dfsg-4CVE-2021-20221

qemuUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-block-extraUbuntu

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-commonUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

qemu-guest-agentUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-keymapsUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

qemu-kvmUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-systemUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-aarch64Ubuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

qemu-system-armUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-commonUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-dataUbuntu

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-guiUbuntu

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-mipsUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

qemu-system-miscUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-ppcUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-system-s390xUbuntu

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

qemu-system-sparcUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

qemu-system-x86Ubuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.37USN-5010-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

qemu-system-x86-microvmUbuntu

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

qemu-system-x86-xenUbuntu

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Fixed in:1:4.2-3ubuntu6.17USN-5010-1

qemu-userUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-user-binfmtUbuntu

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-user-staticUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

qemu-utilsUbuntu

Fixed in:2.0.0+dfsg-2ubuntu1.47+esm6USN-8412-1

Fixed in:1:2.5+dfsg-5ubuntu10.51+esm4USN-8412-1

Fixed in:1:2.11+dfsg-1ubuntu7.42+esm5USN-8412-1

Fixed in:1:4.2-3ubuntu6.30+esm1USN-8412-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

Exploit Intelligence

0.32%probability of exploitation in 30 days

24thpercentile

Low risk: more likely to be exploited than 24% of all known CVEs.

References

Patch2

Third-Party Advisory3

Related Vulnerabilities

Other CWE-125 (Out-of-bounds Read) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0160	High	7.5	100%	KEV	Fix
CVE-2025-5777	High	7.5	100%	KEV + Ransom	Fix
CVE-2021-4034	High	7.8	95%	KEV	Fix
CVE-2023-21769	High	7.5	92%	-	Fix
CVE-2023-49285	High	8.6	89%	-	Fix
CVE-2020-8794	Critical	9.8	89%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.