CVE-2011-3402 Microsoft Windows: command or code injection
In plain words: The program treats text it receives as instructions instead of plain data. The attacker can run commands on the machine — often the whole device is taken over.
Confirmed exploited by CISA on · US federal patch deadline Oct 27, 2025
What to do
- Install Microsoft's security update for Windows. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Turn on automatic updates for the operating system and for Office, PDF and archive apps.
- Be careful with unexpected attachments — documents, .zip/.rar files and shortcuts are common bait.
- Use a normal (non-admin) account day to day and keep built-in protection like Microsoft Defender on.
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: Your files, saved passwords and accounts. Many of these let a program that is already running gain full administrator control.
The details
- Official name
- Microsoft Windows Remote Code Execution Vulnerability
- Product
- Microsoft Windows
- CISA description
- Microsoft Windows Kernel contains an unspecified vulnerability in the TrueType font parsing engine in win32k.sys in the kernel-mode drivers that allows remote attackers to execute arbitrary code via crafted font data in a Word document or web page.
- Type of flaw
- Command or code injection
- Confirmed exploited
- Oct 6, 2025
- US federal patch deadline
- Oct 27, 2025
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Answering about CVE-2011-3402 ·
Questions about CVE-2011-3402
Is CVE-2011-3402 being exploited?
Yes. CISA added CVE-2011-3402 to its Known Exploited Vulnerabilities catalog on Oct 6, 2025, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2011-3402?
Install Microsoft's security update for Windows. If no update exists, follow the vendor's workaround or stop using the product until one ships. Turn on automatic updates for the operating system and for Office, PDF and archive apps.
Am I affected by CVE-2011-3402?
Only if you use Microsoft Windows. This one is aimed at devices or apps of the kind people own.