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HIGH · CVSS 8.8 CISA Known Exploited Vulnerability

CVE-2011-3402

Microsoft Windows Remote Code Execution Vulnerability

Microsoft Windows

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."

CVSS
8.8
HIGH
EPSS
78.1%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
4 Nov 2011
NVD

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 6 October 2025. US federal agencies were required to remediate it by 27 October 2025.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 78.1%, which is higher than 99.6% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2011-3402 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2011-3402.

What does CVE-2011-3402 affect?

CVE-2011-3402 affects Microsoft Windows. 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."

How severe is CVE-2011-3402?

CVE-2011-3402 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 78.1%, higher than 99.6% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 27 October 2025.

How should organisations respond to CVE-2011-3402?

Apply the vendor patch for Microsoft Windows as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.