dbcve.org
Windows 2003 ServerOperating system · Microsoft

CVE-2011-0654

HIGH · 10.0 CVSS v2.0 Published 2011-02-16
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
High EPSS Public exploit 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
Integer underflow in the BowserWriteErrorLogEntry function in the Common Internet File System (CIFS) browser service in Mrxsmb.sys or bowser.sys in Active Directory 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 attackers to execute arbitrary code or cause a denial of service (system crash) via a malformed BROWSER ELECTION message, leading to a heap-based buffer overflow, aka "Browser Pool Corruption Vulnerability." NOTE: some of these details are obtained from third party information.

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

Integer underflow in the BowserWriteErrorLogEntry function in the CIFS browser service (Mrxsmb.sys or bowser.sys) allows remote attackers to execute arbitrary code via malformed BROWSER ELECTION messages, causing a heap-based buffer overflow (Browser Pool Corruption). This is a pre-authentication remote code execution vulnerability in the SMB browser service.

MitigationApply Microsoft security updates for CVE-2011-0654 to all affected Windows systems; until patched, consider disabling the CIFS Browser service or blocking UDP ports 138/445 at network boundaries to reduce attack surface.

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

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. Verify the Windows version
    Run 'winver' or check system properties (sysdm.cpl) to confirm the exact Windows version and build number
    Affected if The system is running Windows Server 2003 or Windows 2003 Server (any version)
  2. Identify if the Browser service is running
    Open Services (services.msc) and locate the 'Computer Browser' service, or run 'sc query browservice' from command prompt
    Affected if The Computer Browser service is running (this service hosts the vulnerable bowser.sys driver)
  3. Check for open SMB browser ports
    Run 'netstat -an | findstr "138\|445"' to see if UDP ports 138 and 445 are listening, or use PortQry.exe with -e parameter
    Affected if UDP port 138 (Browser service) or port 445 (SMB) is open and listening on the system
  4. Verify the bowser.sys driver is loaded
    Run 'driverquery /v | findstr bowser' or check Device Manager for hidden devices, or look for bowser.sys in %SystemRoot%\System32\drivers\
    Affected if The bowser.sys driver is loaded and active on the system

A user is affected if the system is Windows Server 2003 (any version) with the Computer Browser service running and UDP ports 138 or 445 exposed.

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 updates for CVE-2011-0654 to all affected Windows systems; until patched, consider disabling the CIFS Browser service or blocking UDP ports 138/445 at network boundaries to reduce attack surface.

Recommended fix High confidence

Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, or Windows Server 2022

  1. 1. Note that Windows Server 2003 reached End of Support on July 14, 2015 and no longer receives security updates from Microsoft.
  2. 2. Plan and schedule migration from Windows Server 2003 to a supported operating system such as Windows Server 2012 R2, 2016, 2019, or 2022.
  3. 3. Before migration, apply the historical Microsoft security update MS11-020 (Cumulative Security Update for Internet Explorer) if still available through Microsoft Security Response Center for interim protection.
  4. 4. Migrate applications and services to the new Windows Server version.
  5. 5. Verify all functionality works correctly on the new system.
  6. 6. Decommission the Windows Server 2003 systems after successful migration.
Caveat Full migration from Windows Server 2003 may require application re-certification, driver updates, and potential hardware changes; applications written for older OS may need modification or replacement

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

Fix this in Windows 2003 Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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Scan for this in your stack

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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-2011-0654 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