CVE-2021-3559 [Medium] | Memory Corruption in Libvirt

A flaw was found in libvirt in the virConnectListAllNodeDevices API in versions before 7.0.0. It only affects hosts with a PCI device and driver that supports mediated devices (e.g., GRID driver). This flaw could be used by an unprivileged client with a read-only connection to crash the libvirt daemon by executing the 'nodedev-list' virsh command. The highest threat from this vulnerability is to system availability.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.37%	1.03%	+0.67%
2	2025-04-28	0.48%	0.37%	-0.11%
3	2025-03-30	—	0.48%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.37%

1.03%

+0.67%

2025-04-28

0.48%

0.37%

-0.11%

2025-03-30

—

0.48%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	3.6	[email protected]
4.0	2.0	MEDIUM	`AV:N/AC:L/Au:S/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:S) A single authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	8.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

3.6

[email protected]

4.0

2.0

MEDIUM

AV:N/AC:L/Au:S/C:N/I:N/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:S): A single authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

8.0

2.9

[email protected]

OS Trackers for CVE-2021-3559

vendor	priority	summary	link
`debian`	unimportant	CVE-2021-3559 unimportant priority: Debian including 1 source packages (libvirt), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2021-3559
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-3559
`suse`	medium	CVE-2021-3559 severity moderate: SUSE including 35 source package names (libvirt, libvirt-admin, …), 924 product×package rows across 51 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (51 product lines)): Known Not Affected 924.	https://www.suse.com/security/cve/CVE-2021-3559/
`ubuntu`	medium	CVE-2021-3559 medium priority: Ubuntu including 1 source packages (libvirt), 9 status rows across 9 suites (bionic, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): not-affected 9.	https://ubuntu.com/security/CVE-2021-3559

Affected software / configurations for CVE-2021-3559

Vendor	Product	Version	Raw CPE
redhat	libvirt	>= 6.10.0, < 7.0.0	cpe:2.3:a:redhat:libvirt::::::::
netapp	ontap_select_deploy_administration_utility	—	cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:::::::*

References for CVE-2021-3559

URL	Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1962306	Issue Tracking Patch Vendor Advisory
https://security.netapp.com/advisory/ntap-20210706-0006/	Third Party Advisory

URL

CVE-2021-3559

Exploit prediction scoring system (EPSS) score for CVE-2021-3559

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3559

Weakness enumeration for CVE-2021-3559

OS Trackers for CVE-2021-3559

Affected software / configurations for CVE-2021-3559

References for CVE-2021-3559