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Parallels DesktopApplication · Parallels

CVE-2021-31417

MEDIUM · 6.5 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 →
67/100
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 15.1.4-47270. 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 Toolgate component. The issue results from the lack of proper initialization of memory prior to accessing it. 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-12131.

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 an information disclosure vulnerability in Parallels Desktop's Toolgate component. The flaw stems from accessing uninitialized memory, which can leak sensitive data. While the attacker requires low-privileged code execution on the guest VM first, this vulnerability can be chained with other issues to achieve hypervisor escape and execute arbitrary code at the hypervisor level.

MitigationUpdate Parallels Desktop to a patched version. Until then, restrict code execution privileges on guest VMs and minimize the attack surface by limiting which users can interact with the guest system.

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:= 15.1.4-47270

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
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/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. Verify Parallels Desktop is installed
    Check for the application at /Applications/Parallels Desktop.app or list installed applications using 'ls /Applications' or 'system_profiler SPApplicationsDirectoryType'
    Affected if Parallels Desktop.app is not found in /Applications - the system is not using this product
  2. Identify the installed Parallels Desktop version
    Run 'system_profiler SPApplicationsDirectoryType | grep -i parallels' or check the app bundle version: 'defaults read /Applications/Parallels\ Desktop.app/Contents/Info CFBundleShortVersionString'
    Affected if The version returned does not match exactly 15.1.4-47270 - but also check build number below
  3. Check the build number of Parallels Desktop
    Run 'defaults read /Applications/Parallels\ Desktop.app/Contents/Info CFBundleVersion' or inspect the app info.plist for the build identifier
    Affected if The build number is exactly 47270 (this specific build is vulnerable)
  4. Verify if Toolgate component is present
    Check for Toolgate-related files or services: 'ls /Library/Parallels/ | grep -i toolgate' or 'ls /usr/lib/parallels/ | grep -i toolgate'
    Affected if Toolgate component files exist on the system - the vulnerable component is present
  5. Check for active Parallels processes indicating Toolgate usage
    Run 'ps aux | grep -i prl' to list running Parallels processes; check if prl_client or toolgate-related services are active
    Affected if Parallels is actively running with guest VMs - the Toolgate interface may be accessible from the guest

A system is affected only if Parallels Desktop version 15.1.4 with build 47270 is installed and running, enabling the Toolgate component to leak information from uninitialized memory.

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

Update Parallels Desktop to a patched version. Until then, restrict code execution privileges on guest VMs and minimize the attack surface by limiting which users can interact with the guest system.

Fix this in Parallels Desktop Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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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-2021-31417 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
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