CVE-2011-1869
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 · uneditedThe Distributed File System (DFS) implementation in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote DFS servers to cause a denial of service (system hang) via a crafted referral response, aka "DFS Referral Response 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 · high confidenceA denial of service vulnerability in the Windows DFS (Distributed File System) client allows a remote malicious DFS server to send a crafted referral response that causes the client system to hang. The vulnerability exists in how Windows parses and handles DFS referral responses.
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 dataall versionsall versionsall versionsall versions= r2all versionsall versionsCVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
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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Check Windows versionRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the installed Windows version and build numberAffected if The version is Windows XP, Vista, 2003 Server, 2008/2008 R2, or Windows 7 (any service pack)
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Verify DFS client component is installedCheck if the DFS client service is present: open Services console (services.msc) and look for 'DFS Client' service, or run 'sc query dfs' to query the service statusAffected if The DFS Client service exists and is installed on the system (vulnerability only affects systems with DFS client functionality)
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Check for active DFS client configurationRun 'dfsutil /client' or check registry key HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters for EnableDFSR or check for DFS namespace connections via 'dfsutil /clientenum'Affected if The system is configured as an active DFS client (has DFS referrals or namespace connections configured)
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Identify DFS referral usageRun 'net view \\server' (where server is a DFS namespace) or check for mapped drives or shortcuts pointing to DFS paths, or run 'dfscmd /view' to see configured DFS rootsAffected if The system has recently accessed or configured DFS namespaces, indicating active DFS client behavior
A system is affected if it runs any of the affected Windows versions (XP through 7, Server 2003/2008/2008 R2, Vista) AND has the DFS client component enabled or configured, as the vulnerability is triggered by processing malicious DFS referral responses.
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 the Microsoft security patch for CVE-2011-1869 to all affected Windows systems (XP SP2/SP3, Server 2003 SP2, Vista SP1/SP2, Server 2008, Server 2008 R2, Windows 7 Gold/SP1). For systems no longer supported, consider upgrading or implementing network-level controls to restrict DFS communications to trusted servers.
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- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2011-1869 — 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-2011-1869 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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