CVE-2021-27242

Guest-to-hypervisor privilege escalation via Toolgate memory corruption

Published Mar 29, 2021 · Updated Aug 3, 2024

A memory corruption vulnerability in Parallels Desktop 16.0.1-48919 allows local users to escalate privileges via the Toolgate component. Toolgate fails to validate user-supplied data, enabling memory corruption that crosses from the guest into the hypervisor. Exploitation requires low-privileged code execution inside a guest and can result in hypervisor-context code execution.

CVSS severity8.8
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A memory corruption vulnerability in Parallels Desktop 16.0.1-48919 allows local users to escalate privileges via the Toolgate component. Toolgate fails to validate user-supplied data, enabling memory corruption that crosses from the guest into the hypervisor. Exploitation requires low-privileged code execution inside a guest and can result in hypervisor-context code execution.

The record

CVE
CVE-2021-27242
Published
Mar 29, 2021
Updated
Aug 3, 2024
Vendor
Parallels
Product
Parallels Desktop
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 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=16.0.1-48919

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Parallels · Parallels Desktopversion=16.0.1-48919

Published CVSS scores

8.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.8Trend Micro ZDICVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
4.6NVDAV:L/AC:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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