CVE-2019-11868
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 · uneditedSee.sys, up to version 4.25, in SoftEther VPN Server versions 4.29 or older, allows a user to call an IOCTL specifying any kernel address to which arbitrary bytes are written to.
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 confidenceThe See.sys kernel driver in SoftEther VPN Server versions 4.29 and older contains an arbitrary kernel memory write vulnerability. The driver accepts IOCTL calls that allow specifying any kernel address to which arbitrary bytes are written, enabling local privilege escalation from unprivileged user context to kernel 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<= 4.25CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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 SoftEther VPN Server installationSearch for SoftEther VPN Server installation directories (common paths: C:\Program Files\SoftEther VPN Server on Windows, /usr/lib/softether/vpnserver or /opt/softether on Linux). Look for the presence of see.sys or vpn_server module files.Affected if SoftEther VPN Server software is installed on the system
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Check installed SoftEther versionReview the SoftEther VPN Server version information - this is typically displayed in the server admin console, found in version.txt, or viewable through the vpncmd utility with the /version flag. Compare against affected versions.Affected if Installed version is 4.25 or older (or any version <= 4.29 where the driver has not been updated)
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Verify See.sys driver presenceCheck for the see.sys file in the installation directory on Windows. On Linux, check for the vpnserver process and look for loaded kernel modules related to SoftEther (lsmod | grep -i softether or checking /proc/modules).Affected if The See.sys driver file exists or the SoftEther kernel driver module is loaded into memory
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Confirm driver IOCTL interface accessibilityThe vulnerability requires the driver to be loaded and accepting IOCTL calls. On Windows, verify the driver service status is Running. On Linux, verify the vpnserver daemon is actively running.Affected if The See.sys driver is actively running and the vpnserver service is operational, enabling the IOCTL attack surface
If SoftEther VPN Server version 4.25 or older is installed and the See.sys kernel driver is present and loaded, the system is affected by CVE-2019-11868.
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 SoftEther VPN Server to a version newer than 4.29, which contains the patched See.sys driver. Restrict access to the VPN service and driver IOCTL interface until the update can be applied.
- Consultation4.0 h
- Implementation2.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-11868 — 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-2019-11868 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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