CVE-2021-4206

Name: CVE-2021-4206
Creator: NVD / NIST
Published: 2022-04-29T17:15:20.023+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.2/10EPSS 0.83%

Last modified Jun 17, 2026

CVE-2021-4206 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. A flaw was found in the QXL display device emulation in QEMU. An integer overflow in the cursor_alloc() function can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. EPSS estimates a 0.83% chance of exploitation in the next 30 days.

Description

A flaw was found in the QXL display device emulation in QEMU. An integer overflow in the cursor_alloc() function can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. This flaw allows a malicious privileged guest user to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.

Metrics

CVSS 3.1

8.2/10

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

EPSS Probability

0.83%

53.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Qemu	Qemu	< 7.0.0
Redhat	Enterprise Linux	8.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=2036998Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
https://security.gentoo.org/glsa/202208-27Third Party Advisory
https://starlabs.sg/advisories/21-4206/Exploit, Third Party Advisory
https://www.debian.org/security/2022/dsa-5133Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2036998Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
https://security.gentoo.org/glsa/202208-27Third Party Advisory
https://security.netapp.com/advisory/ntap-20250321-0010/
https://starlabs.sg/advisories/21-4206/Exploit, Third Party Advisory
https://www.debian.org/security/2022/dsa-5133Third Party Advisory

Timeline

Published: Apr 29, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-4206?

How severe is CVE-2021-4206?

CVE-2021-4206 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.83% probability of exploitation in the next 30 days.

How do I fix CVE-2021-4206?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-4206?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST