CVE-2021-3559Network attack vector

Daemon crash via incorrect array-pointer dereference

Published May 24, 2021 · Updated Aug 3, 2024

Memory corruption in libvirt 6.10.0 through 7.0.0 release candidates allows remote authenticated users to crash libvirtd via node-device listing. Incorrect operator precedence in virNodeDeviceGetMdevTypesCaps dereferences the array pointer incorrectly while clearing mediated-device type entries. A read-only connection is sufficient, but the host must have a PCI device and driver that supports mediated devices; successful exploitation interrupts virtualization management.

CVSS severity6.5
Medium
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in libvirt 6.10.0 through 7.0.0 release candidates allows remote authenticated users to crash libvirtd via node-device listing. Incorrect operator precedence in virNodeDeviceGetMdevTypesCaps dereferences the array pointer incorrectly while clearing mediated-device type entries. A read-only connection is sufficient, but the host must have a PCI device and driver that supports mediated devices; successful exploitation interrupts virtualization management.

The record

CVE
CVE-2021-3559
Published
May 24, 2021
Updated
Aug 3, 2024
Vendor
Red Hat
Product
libvirt
Classifications
CWE-119, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=libvirt 7.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Red Hat · libvirtversion=libvirt 7.0.0

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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