CVE-2021-31418
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 · uneditedThis 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-12221.
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 confidenceUninitialized memory read vulnerability in Parallels Desktop's Toolgate component allows a low-privileged guest user to potentially read sensitive memory contents, which can be chained with other vulnerabilities to achieve hypervisor escape and execute arbitrary code at the hypervisor level.
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= 15.1.4-47270CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify Parallels Desktop installationOn the macOS host, open Parallels Desktop and go to Parallels Desktop menu > About Parallels Desktop, or run 'prlctl list -a' from Terminal to list all VMsAffected if Parallels Desktop is installed on the system
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Determine installed Parallels Desktop versionIn About window, note the full version number and build (e.g., 15.1.4-47270). On command line, run 'prlctl --version' to get version and build detailsAffected if The installed version is 15.1.4-47270 or earlier (vulnerable); the fixed version is later than 15.1.4-47270
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Confirm Toolgate component is in useThe vulnerability resides in the Toolgate component. Check if the affected VM has Parallels Tools installed: run 'prlctl list -i <vm_name>' and look for 'Parallels Tools' status, or inspect the VM configuration for enabled device connectionsAffected if Parallels Tools are installed and active in the guest VM, enabling the Toolgate communication channel
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Verify guest user access to the VMConfirm that untrusted or low-privileged users have access to run code inside the guest VM. Review VM sharing settings and user permissions in System Preferences > Users & Groups or via 'dscl . -list /Users'Affected if Untrusted or low-privileged users can execute code within the guest virtual machine
The environment is affected if Parallels Desktop version 15.1.4-47270 or earlier is installed with Parallels Tools enabled in a guest VM accessible to untrusted users.
Generated from the published advisory. Verify against your own configuration.
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 dataApply vendor patch from Parallels - update to version 15.1.4-47270 or later. Minimize attack surface by restricting VM access to trusted users only since the attacker requires prior code execution on the guest system.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-31418 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-31418 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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