CVE-2021-31847
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 · uneditedImproper access control vulnerability in the repair process for McAfee Agent for Windows prior to 5.7.4 could allow a local attacker to perform a DLL preloading attack using unsigned DLLs. This would result in elevation of privileges and the ability to execute arbitrary code as the system user, through not correctly protecting a temporary directory used in the repair process and not checking the DLL signature.
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 confidenceMcAfee Agent for Windows prior to version 5.7.4 contains an improper access control vulnerability in its repair process. The repair functionality uses a temporary directory that is not adequately protected, and the application fails to validate DLL signatures before loading them. A local attacker can place a malicious unsigned DLL in this temp directory to achieve DLL preloading, resulting in elevation of privileges to SYSTEM level and arbitrary code execution.
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< 5.7.4CVSS 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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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Verify McAfee Agent is installedCheck for McAfee Agent installation by looking for the product in Add/Remove Programs, or check for the existence of the McAfee Agent program directory (typically at C:\Program Files\McAfee\Agent or C:\Program Files (x86)\McAfee\Agent).Affected if McAfee Agent is present on the system.
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Identify installed McAfee Agent versionLocate the McAfee Agent version by checking the agent.exe file properties (right-click on agent.exe in the installation directory and view Details tab), or run the command 'agent --version' from the McAfee Agent bin directory, or check the Windows registry under HKLM\SOFTWARE\McAfee\Agent with the key 'AgentVersion'.Affected if The installed version is lower than 5.7.4.
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Confirm repair functionality is accessibleAttempt to access the repair functionality through the McAfee Agent context menu (right-click the McAfee icon in system tray) or by running 'agent --repair' from the command line in the McAfee Agent bin directory.Affected if The repair feature is available and executable on the system.
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Check temp directory permissions and usageDuring or after running the repair function, observe which temporary directory the McAfee Agent creates and uses. On Windows, this is typically found in the user temp folder (%TEMP%) or in C:\Windows\Temp. Verify if low-privileged users can write to this directory.Affected if The repair process uses a temp directory that allows write access from standard user accounts.
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Inspect loaded DLLs for signature validationUse Process Explorer or similar tool to view DLLs loaded by the agent.exe process while the repair function runs. Check if any DLLs loaded from the temp directory are missing valid digital signatures.Affected if DLLs are loaded from the temp directory without verifying digital signatures.
The system is affected if McAfee Agent for Windows version 5.7.4 or higher is NOT installed, and the repair functionality can be triggered with a temp directory writable by lower-privileged 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.
dbcve · scoped5.7.4
Upgrade McAfee Agent for Windows to version 5.7.4 or later to address the unprotected temporary directory and missing DLL signature validation.
McAfee Agent 5.7.4 or later
- Identify all systems running McAfee Agent for Windows with version prior to 5.7.4
- Download McAfee Agent version 5.7.4 or later from the official McAfee download portal or your management console
- Apply the agent update to all affected Windows systems
- Verify the McAfee Agent version has been updated to 5.7.4 or later using the McAfee ePO console or by checking the agent version locally
- Confirm the repair process no longer uses unprotected temporary directories and validates DLL signatures
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 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-2021-31847 — 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-2021-31847 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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