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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 27 Oct 2025.
Windows 7Operating system · Microsoft

CVE-2011-3402

HIGH · 8.8 CVSS v3.1 Published 2011-11-04
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
In the wild High EPSS Remotely reachable No privileges

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
Unspecified vulnerability in the TrueType font parsing engine in win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code via crafted font data in a Word document or web page, as exploited in the wild in November 2011 by Duqu, aka "TrueType Font Parsing 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

Vulnerability in TrueType font parsing engine in win32k.sys (kernel-mode driver) allows remote code execution via crafted font data embedded in Word documents or web pages. The vulnerability was exploited in the wild by the Duqu malware in 2011.

MitigationApply Microsoft security update MS11-087 which addresses this vulnerability; for unsupported legacy systems, disable embedded font rendering in Office applications and deploy exploit mitigation tools such as EMET or Windows Defender Exploit Guard.

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 7Operating system
Affected:all versions
Windows Server 2003Operating system
Affected:all versions
Windows Server 2008Operating system
Affected:all versions
Windows VistaOperating 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
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checks

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

  1. Verify Windows version is affected
    Run 'winver' or check System Properties to confirm the Windows version. Affected versions are Windows XP, Vista, 7, and Windows Server 2003/2008 (all versions).
    Affected if The system runs any unpatched version of Windows XP, Vista, 7, Server 2003, or Server 2008.
  2. Check if MS11-087 security update is installed
    Open Control Panel > Programs and Features > View installed updates, or run 'wmic qfe list' command. Look for security update KB2631813.
    Affected if The security update KB2631813 is not listed among installed updates.
  3. Verify win32k.sys version
    Navigate to C:\Windows\System32\win32k.sys, right-click > Properties > Details tab, and check the File Version. Compare against the patched version (for example, on Windows 7 SP1 the patched version is 6.1.7601.17787).
    Affected if The win32k.sys version is older than the patched versions released in December 2011.
  4. Confirm vulnerability exposure through font loading
    Review whether the system has applications that parse embedded fonts from untrusted sources, such as opening Word documents or viewing web pages with custom fonts.
    Affected if Users open documents or browse web pages from untrusted sources without the security update applied.

The system is affected if it runs an unpatched Windows XP, Vista, 7, Server 2003, or Server 2008 version and lacks the KB2631813 security update.

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 MS11-087 which addresses this vulnerability; for unsupported legacy systems, disable embedded font rendering in Office applications and deploy exploit mitigation tools such as EMET or Windows Defender Exploit Guard.

Recommended fix High confidence

If the operating system is end-of-life (Windows XP, Vista, Server 2003), upgrade to a supported Windows version (Windows 10/11 or Windows Server 2016/2019/2022) as no further patches will be available

  1. Identify the exact Windows version and Service Pack level by running 'winver' or checking System Properties
  2. For Windows XP SP2/SP3: Apply Microsoft Security Bulletin MS11-087 (out-of-band update released December 22, 2011) from the Microsoft Update Catalog or Windows Update
  3. For Windows Server 2003 SP2: Apply MS11-087 from Microsoft Update Catalog or Windows Update
  4. For Windows Vista SP2: Apply MS11-087 from Microsoft Update Catalog or Windows Update
  5. For Windows Server 2008 SP2/R2: Apply MS11-087 from Microsoft Update Catalog or Windows Update
  6. For Windows 7 Gold/SP1: Apply MS11-087 from Microsoft Update Catalog or Windows Update
  7. After patching, verify the win32k.sys version matches the KB2496930D update package (typically version 6.1.7600.17727 or higher for Windows 7, verify via 'systeminfo' or File Properties of win32k.sys in C:\Windows\System32)
  8. Restart the affected system to complete the patch installation
Caveat None for patching; however, Windows XP, Vista, and Server 2003 are end-of-life and no longer receive security updates, requiring migration to supported OS versions for ongoing protection

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

Fix this in Windows 7 Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2011-3402 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