CVE-2026-68820 Microsoft Windows Ancillary Function Driver for WinSock: 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 Aug 25, 2026
What to do
- Install Microsoft's security update for Windows Ancillary Function Driver for WinSock. 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 Ancillary Function Driver for WinSock Use-After-Free Vulnerability
- Product
- Microsoft Windows Ancillary Function Driver for WinSock
- CISA description
- Microsoft Windows Ancillary Function Driver for WinSock contains a use-after-free vulnerability that allows an authorized attacker to elevate privileges locally.
- Type of flaw
- Memory-safety flaw (CWE-416)
- Confirmed exploited
- Aug 11, 2026
- US federal patch deadline
- Aug 25, 2026
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Answering about CVE-2026-68820 ·
Questions about CVE-2026-68820
Is CVE-2026-68820 being exploited?
Yes. CISA added CVE-2026-68820 to its Known Exploited Vulnerabilities catalog on Aug 11, 2026, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2026-68820?
Install Microsoft's security update for Windows Ancillary Function Driver for WinSock. 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-2026-68820?
Only if you use Microsoft Windows Ancillary Function Driver for WinSock. This one is aimed at devices or apps of the kind people own.