CVE-2021-20196

Description

A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
qemu	25.10 questing	Fixed 1:6.2+dfsg-2ubuntu5
	25.04 plucky	Fixed 1:6.2+dfsg-2ubuntu5
	24.10 oracular	Fixed 1:6.2+dfsg-2ubuntu5
	24.04 LTS noble	Fixed 1:6.2+dfsg-2ubuntu5
	23.10 mantic	Fixed 1:6.2+dfsg-2ubuntu5
	23.04 lunar	Fixed 1:6.2+dfsg-2ubuntu5
	22.10 kinetic	Fixed 1:6.2+dfsg-2ubuntu5
	22.04 LTS jammy	Fixed 1:6.2+dfsg-2ubuntu5
	21.10 impish	Fixed 1:6.0+dfsg-2expubuntu1.2
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 1:4.2-3ubuntu6.21
	18.04 LTS bionic	Fixed 1:2.11+dfsg-1ubuntu7.39
	16.04 LTS xenial	Vulnerable
	14.04 LTS trusty	Vulnerable
qemu-kvm	25.10 questing	Not in release
	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	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
xen	25.10 questing	Needs evaluation
	25.04 plucky	Needs evaluation
	24.10 oracular	Ignored end of life, was needs-triage
	24.04 LTS noble	Needs evaluation
	23.10 mantic	Ignored end of life, was needs-triage
	23.04 lunar	Ignored end of life, was needs-triage
	22.10 kinetic	Ignored end of life, was needs-triage
	22.04 LTS jammy	Needs evaluation
	21.10 impish	Ignored end of life
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Not in release

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=1ab95af033a419e7a64e2d58e67dd96b20af5233

Severity score breakdown

Parameter	Value
Base score	6.5 · Medium
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Changed
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-5307-1
QEMU vulnerabilities
28 February 2022