Parallels DesktopApplication · Parallels

CVE-2021-31427

MEDIUM · 5.6 CVSS v3.1 Published 2021-04-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
This vulnerability allows local attackers to disclose sensitive information on affected installations of Parallels Desktop 15.1.5-47309. An attacker must first obtain the ability to execute low-privileged code on the target guest system in order to exploit this vulnerability. The specific flaw exists within the Open Tools Gate component. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute arbitrary code in the context of the hypervisor. Was ZDI-CAN-13082.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a race condition vulnerability in Parallels Desktop's Open Tools Gate component. The flaw stems from improper locking mechanisms when performing operations on objects, allowing a low-privileged attacker with guest system code execution to potentially escalate privileges to the hypervisor level when chained with other vulnerabilities.

MitigationApply available vendor patches for Parallels Desktop. Additionally, minimize the attack surface by restricting execution of untrusted code within guest virtual machines and keeping guest systems hardened.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Parallels DesktopApplication
Affected:= 15.1.5-47309

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Parallels Desktop is installed
    Check for the Parallels Desktop application in /Applications folder on macOS, or query installed applications via system utilities
    Affected if Parallels Desktop is not installed on the system
  2. Identify installed Parallels Desktop version
    Open Parallels Desktop and navigate to Parallels Desktop menu > About Parallels Desktop, or run: defaults read /Applications/Parallels\ Desktop.app/Contents/Info.plist CFBundleVersion
    Affected if Version matches 15.1.5-47309 exactly
  3. Verify Open Tools Gate component status
    Check if Parallels Tools (formerly Open Tools) are installed and running in the guest virtual machine. Inspect guest VM configuration for installed tools.
    Affected if Parallels Tools/Open Tools are installed and active in any guest VM
  4. Assess guest VM code execution risk
    Review whether untrusted or potentially malicious code can execute within any guest virtual machines running on this installation
    Affected if Untrusted code execution is permitted within guest virtual machines

User is affected if Parallels Desktop version 15.1.5-47309 is installed AND Parallels Tools/Open Tools are enabled in guest VMs, with potential for untrusted code execution inside those guests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply available vendor patches for Parallels Desktop. Additionally, minimize the attack surface by restricting execution of untrusted code within guest virtual machines and keeping guest systems hardened.

Fix this in Parallels Desktop Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-31427 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-31427 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data