dbcve.org
Windows 2003 ServerOperating system · Microsoft

CVE-2011-1868

HIGH · 10.0 CVSS v2.0 Published 2011-06-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
The Distributed File System (DFS) implementation in Microsoft Windows XP SP2 and SP3 and Server 2003 SP2 does not properly validate fields in DFS responses, which allows remote DFS servers to execute arbitrary code via a crafted response, aka "DFS Memory Corruption 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 confidence

A memory corruption vulnerability exists in the Windows DFS (Distributed File System) client implementation. The client fails to properly validate fields in DFS responses received from remote DFS servers, allowing a malicious or compromised DFS server to send crafted responses that trigger memory corruption and enable arbitrary code execution on the client system.

MitigationApply Microsoft security update MS11-039 which addresses this vulnerability. For systems that cannot be patched (Windows XP/Server 2003 are end-of-life), network segment DFS traffic and restrict communication to trusted DFS servers only.

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
Windows 2003 ServerOperating system
Affected:all versions
Windows Server 2003Operating system
Affected:all versions
Windows XpOperating system
Affected:all versions

CVSS 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
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Windows version
    Open Command Prompt and run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"'. Verify the system is Windows XP or Windows Server 2003.
    Affected if The operating system is Windows XP (any version) or Windows Server 2003 (any version)
  2. Verify DFS client service is present
    Open Services console (services.msc) or run 'sc query dfs' from command prompt. Check if the 'DFS Client' service (service name: Dfs) exists on the system.
    Affected if The Dfs service exists on the system (it is a built-in component of affected Windows versions)
  3. Check if DFS client is running or enabled
    Run 'sc queryex dfs' or check the service status in services.msc. Also check for startup type using 'sc qc dfs'.
    Affected if The DFS service is set to Automatic or Manual startup and is currently running or has been run previously
  4. Identify active DFS connections
    Run 'net use' or 'dfsutil client info' (if available) to list mapped drives and UNC paths that may be using DFS namespaces. Check for any DFS-mounted resources.
    Affected if The system has active DFS connections or mapped drives pointing to DFS namespaces
  5. Check for DFS client driver
    Open Device Manager, expand 'System devices', and look for 'Microsoft DFS Client Driver (Mup.sys)' or run 'driverquery | findstr dfs'
    Affected if The Microsoft DFS Client Driver (Mup.sys) is present on the system

The system is likely affected if it runs Windows XP or Windows Server 2003 and has the DFS client service enabled or has established connections to DFS namespaces.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft security update MS11-039 which addresses this vulnerability. For systems that cannot be patched (Windows XP/Server 2003 are end-of-life), network segment DFS traffic and restrict communication to trusted DFS servers only.

Recommended fix High confidence

Windows Server 2008 R2 or later for servers; Windows 7 or later for clients (both receive ongoing security updates)

  1. 1. Identify all systems running Windows XP (SP2/SP3) or Windows Server 2003 (SP2) on the network that use DFS functionality.
  2. 2. Back up critical data and document current configuration.
  3. 3. Assess application compatibility for migrating to a supported Windows version (Windows Server 2008 R2 or later, Windows 7 or later).
  4. 4. For systems that cannot be immediately upgraded, apply the historical Microsoft patch MS11-039 if available through your volume licensing or extended support agreement.
  5. 5. Plan and execute migration to supported operating systems: Windows Server 2008 R2/2012/2016/2019/2022 for servers, Windows 7/8.1/10 for clients.
  6. 6. After migration, verify DFS functionality works correctly with the new operating system version.
  7. 7. Ensure the new systems are enrolled in a supported patching program for ongoing security updates.
Caveat Migration from Windows XP/Server 2003 to newer Windows versions may require application re-certification, driver updates, and potential Active Directory schema updates; some legacy applications may not be compatible with modern OS versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 2003 Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2011-1868 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data