CVE-2021-31422

Hypervisor code execution via e1000e locking race

Published Apr 29, 2021 · Updated Aug 3, 2024

Improper locking in Parallels Desktop 16.1.1-49141 allows local users to execute arbitrary code in the hypervisor from a guest. The e1000e virtual device performs operations on an object without proper locking, creating a time-of-check/time-of-use race. Exploitation requires high-privileged code execution in the target guest and crosses the virtualization boundary into the hypervisor.

CVSS severity7.5
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in Parallels Desktop 16.1.1-49141 allows local users to execute arbitrary code in the hypervisor from a guest. The e1000e virtual device performs operations on an object without proper locking, creating a time-of-check/time-of-use race. Exploitation requires high-privileged code execution in the target guest and crosses the virtualization boundary into the hypervisor.

The record

CVE
CVE-2021-31422
Published
Apr 29, 2021
Updated
Aug 3, 2024
Vendor
Parallels
Product
Parallels Desktop
Classifications
CWE-367, CWE-667, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 29, 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=16.1.1-49141

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Parallels · Parallels Desktopversion=16.1.1-49141

Published CVSS scores

7.5Zero Day InitiativeCVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
4.4NIST National Vulnerability DatabaseAV:L/AC:M/Au:N/C:P/I:P/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-667Improper Locking
T1068Exploitation for Privilege Escalation

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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