CVE-2026-20809
TOCTOU Race Condition in Windows Kernel Enables Local Privilege Escalation
Publication date: 2026-01-13
Last updated on: 2026-01-13
Assigner: Microsoft Corporation
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| microsoft | windows_kernel | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-122 | A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). |
| CWE-367 | The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a time-of-check time-of-use (toctou) race condition in the Windows Kernel Memory. It allows an authorized attacker to exploit the timing between checking a condition and using a resource, leading to an elevation of privileges locally on the affected system. [1]
How can this vulnerability impact me? :
The vulnerability can allow an authorized attacker to elevate their privileges on the local system. This means the attacker could gain higher-level access than intended, potentially leading to unauthorized actions, data access, or system control. [1]
What immediate steps should I take to mitigate this vulnerability?
Apply the security updates provided by Microsoft for this vulnerability as soon as possible to mitigate the elevation of privilege risk caused by the toctou race condition in Windows Kernel Memory. [1]