Tap Windows6Application · Openvpn
CVE-2024-1305
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 · uneditedtap-windows6 driver version 9.26 and earlier does not properly check the size data of incomming write operations which an attacker can use to overflow memory buffers, resulting in a bug check and potentially arbitrary code execution in kernel space
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 confidenceA buffer overflow vulnerability exists in the tap-windows6 driver (versions 9.26 and earlier) where incoming write operation size data is not properly validated, allowing an attacker to overflow memory buffers. This can trigger a bug check (system crash) or enable arbitrary code execution with kernel-level privileges.
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
Tap Windows6Application
<= 9.26.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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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Locate the tap-windows6 driver fileSearch for tap0901.sys or tap-windows6.sys in C:\Windows\System32\drivers\ and in the OpenVPN installation directory (typically C:\Program Files\OpenVPN\bin\ or C:\Program Files\OpenVPN\driver\)Affected if The driver file exists on the system - OpenVPN or any software using this virtual network adapter must be installed
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Check driver file versionRight-click the tap0901.sys file, select Properties, then go to the Details tab and check the Product Version field. Alternatively, run `Get-Item "C:\Windows\System32\drivers\tap0901.sys" | Format-List *` in PowerShell if the file existsAffected if The reported version is 9.26.0 or earlier, or if no version is displayed (older unversioned builds)
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Check driver via Device ManagerOpen Device Manager, expand Network adapters, look for 'Tap-Windows Adapter V9' or 'OpenVPN Tap-Win32 adapter' or similar TAP adapter entries. Right-click the adapter, select Properties, then go to the Driver tab to view the driver versionAffected if The driver version shown is 9.26 or earlier, indicating an unpatched version
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Check driver via registryRun `reg query "HKLM\SYSTEM\CurrentControlSet\Services\Tap0901" /v ImagePath` to locate the driver path, then inspect the driver's version info from that locationAffected if The driver file found at the registry path has version 9.26.0 or earlier
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Verify OpenVPN version as indicatorIf OpenVPN is installed, check its version by running `openvpn --version` or looking in Add/Remove Programs. OpenVPN installations typically bundle the tap-windows6 driverAffected if OpenVPN version bundles or requires tap-windows6 driver version 9.26 or earlier, but note that the driver version should still be checked directly as it may differ from OpenVPN's version
A system is affected if the tap-windows6 driver (tap0901.sys) is installed and its version is 9.26.0 or earlier, as this version lacks proper size validation for write operations and is vulnerable to buffer overflow.
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 dataUpgrade tap-windows6 driver to version 9.27 or later which contains proper size validation for write operations. Prioritize systems running OpenVPN or other software utilizing this driver.
Fix this in Tap Windows6
Scoped from the published advisory
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-1305 — 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-2024-1305 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
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