CVE-2021-40449 Microsoft Windows: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Dec 1, 2021
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. Used in ransomware, which spreads to ordinary people and small businesses.
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 Win32k Privilege Escalation Vulnerability
- Product
- Microsoft Windows
- CISA description
- Unspecified vulnerability allows for an authenticated user to escalate privileges.
- Type of flaw
- Memory-safety flaw (CWE-416)
- Confirmed exploited
- Nov 17, 2021 — known to be used in ransomware attacks
- US federal patch deadline
- Dec 1, 2021
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Answering about CVE-2021-40449 ·
Questions about CVE-2021-40449
Is CVE-2021-40449 being exploited?
Yes. CISA added CVE-2021-40449 to its Known Exploited Vulnerabilities catalog on Nov 17, 2021, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-40449?
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-2021-40449?
Only if you use Microsoft Windows. Used in ransomware, which spreads to ordinary people and small businesses.