CVE-2021-4206

Publication date 29 April 2022

Last updated 18 August 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

8.2 · High

Score breakdown

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.

Status

Package Ubuntu Release Status
qemu 25.10 questing
Fixed 1:6.2+dfsg-2ubuntu8
25.04 plucky
Fixed 1:6.2+dfsg-2ubuntu8
24.10 oracular
Fixed 1:6.2+dfsg-2ubuntu8
24.04 LTS noble
Fixed 1:6.2+dfsg-2ubuntu8
23.10 mantic
Fixed 1:6.2+dfsg-2ubuntu8
23.04 lunar
Fixed 1:6.2+dfsg-2ubuntu8
22.10 kinetic
Fixed 1:6.2+dfsg-2ubuntu8
22.04 LTS jammy
Fixed 1:6.2+dfsg-2ubuntu6.2
21.10 impish
Fixed 1:6.0+dfsg-2expubuntu1.3
20.04 LTS focal
Fixed 1:4.2-3ubuntu6.23
18.04 LTS bionic
Fixed 1:2.11+dfsg-1ubuntu7.40
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
qemu

Severity score breakdown

Parameter Value
Base score 8.2 · High
Attack vector Local
Attack complexity Low
Privileges required High
User interaction None
Scope Changed
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

Other references