CVE-2023-6340
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 · uneditedSonicWall Capture Client version 3.7.10, NetExtender client version 10.2.337 and earlier versions are installed with sfpmonitor.sys driver. The driver has been found to be vulnerable to Denial-of-Service (DoS) caused by Stack-based Buffer Overflow vulnerability.
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 · moderate confidenceThe sfpmonitor.sys kernel driver in SonicWall Capture Client 3.7.10 and NetExtender client version 10.2.337 and earlier contains a stack-based buffer overflow vulnerability that can be exploited to cause a denial of service. The vulnerability is triggered when the driver processes malformed input, leading to stack memory corruption and system crash.
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<= 3.7.10<= 10.2.337CVSS 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
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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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Identify if SonicWall Capture Client is installedCheck the installed programs list or look for the application in Program Files. Verify the version by checking the executable properties or using 'Get-ItemProperty' in PowerShell for HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\* or checking the application directory for version info.Affected if The installed version is 3.7.10 or lower.
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Identify if SonicWall NetExtender is installedCheck the installed programs list or look for NetExtender in Program Files. Verify the version by checking the executable properties or registry keys under HKLM:\SOFTWARE\SonicWall\NetExtender or HKCU:\SOFTWARE\SonicWall\NetExtender.Affected if The installed version is 10.2.337 or lower.
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Locate the sfpmonitor.sys driver fileSearch for sfpmonitor.sys in the Windows\System32\drivers directory or within the SonicWall application installation folders. Use 'Get-ChildItem -Path C:\ -Filter sfpmonitor.sys -Recurse -ErrorAction SilentlyContinue' or check typical SonicWall install paths.Affected if The driver file exists on the system.
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Check the driver's file versionRight-click the sfpmonitor.sys file, select Properties, and examine the File Version field. Alternatively, use PowerShell: (Get-Item 'C:\path\to\sfpmonitor.sys').VersionInfo.Affected if The file version corresponds to the affected product versions (Capture Client <= 3.7.10 or NetExtender <= 10.2.337).
The system is affected if either SonicWall Capture Client version 3.7.10 or lower, or SonicWall NetExtender version 10.2.337 or lower, is installed and the sfpmonitor.sys driver is present on the system.
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-supplied patches or updates to SonicWall Capture Client and NetExtender to obtain patched versions of the sfpmonitor.sys driver. If updates are unavailable, consider disabling the affected service or implementing network-based controls to limit exposure to adjacent attackers.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-6340 — 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-2023-6340 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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