CVE-2020-27821

Publication date 8 December 2020

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was found in the memory management API of QEMU during the initialization of a memory region cache. This issue could lead to an out-of-bounds write access to the MSI-X table while performing MMIO operations. A guest user may abuse this flaw to crash the QEMU process on the host, resulting in a denial of service. This flaw affects QEMU versions prior to 5.2.0.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
qemu	20.10 groovy	Fixed 1:5.0-5ubuntu9.4
	20.04 LTS focal	Fixed 1:4.2-3ubuntu6.12
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected
qemu-kvm	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release

Notes

mdeslaur

exec.c in earlier releases

Patch details

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

Package	Patch details
qemu	Upstream: https://git.qemu.org/?p=qemu.git;a=commit;h=4bfb024bc76973d40a359476dc0291f46e435442

Severity score breakdown

Parameter	Value
Base score	6.0 · Medium
Attack vector	Local
Attack complexity	Low
Privileges required	High
User interaction	None
Scope	Changed
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H