CVE-2021-32843Public exploit

Host crash via null virtio read handler

Published Feb 17, 2023 · Updated Mar 10, 2025

NULL pointer dereference in HyperKit 0.20210107 and earlier allows guest OS users to crash the host through a virtio-rnd I/O read. In vi_pci_read, an offset beyond the common virtio configuration region calls the device's null vc_cfgread handler instead of rejecting the read. The guest must run with virtio-rnd enabled and issue an out-of-range configuration read; the consequence is a host-process crash.

CVSS severity6.2
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in HyperKit 0.20210107 and earlier allows guest OS users to crash the host through a virtio-rnd I/O read. In vi_pci_read, an offset beyond the common virtio configuration region calls the device's null vc_cfgread handler instead of rejecting the read. The guest must run with virtio-rnd enabled and issue an out-of-range configuration read; the consequence is a host-process crash.

The record

CVE
CVE-2021-32843
Published
Feb 17, 2023
Updated
Mar 10, 2025
Vendor
Moby Project
Product
HyperKit
Classifications
CWE-476, T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Feb 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 2025Record 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=0.20210107 <=0.20210107

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Moby Project · HyperKitversion=0.20210107 <=0.20210107

Published CVSS scores

6.2GitHub CNACVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

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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