CVE-2026-26177
Use-After-Free in Windows WinSock Driver Enables Local Privilege Escalation
Publication date: 2026-04-14
Last updated on: 2026-04-23
Assigner: Microsoft Corporation
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| microsoft | windows_server_2012 | r2 |
| microsoft | windows_server_2012 | * |
| microsoft | windows_10_1607 | to 10.0.14393.9060 (exc) |
| microsoft | windows_10_1607 | to 10.0.14393.9060 (exc) |
| microsoft | windows_10_1809 | to 10.0.17763.8644 (exc) |
| microsoft | windows_10_1809 | to 10.0.17763.8644 (exc) |
| microsoft | windows_10_21h2 | to 10.0.19044.7184 (exc) |
| microsoft | windows_10_21h2 | to 10.0.19044.7184 (exc) |
| microsoft | windows_10_21h2 | to 10.0.19044.7184 (exc) |
| microsoft | windows_10_22h2 | to 10.0.19045.7184 (exc) |
| microsoft | windows_10_22h2 | to 10.0.19045.7184 (exc) |
| microsoft | windows_10_22h2 | to 10.0.19045.7184 (exc) |
| microsoft | windows_11_23h2 | to 10.0.22631.6936 (exc) |
| microsoft | windows_11_23h2 | to 10.0.22631.6936 (exc) |
| microsoft | windows_11_24h2 | to 10.0.26100.8246 (exc) |
| microsoft | windows_11_24h2 | to 10.0.26100.8246 (exc) |
| microsoft | windows_11_25h2 | to 10.0.26200.8246 (exc) |
| microsoft | windows_11_25h2 | to 10.0.26200.8246 (exc) |
| microsoft | windows_11_26h1 | to 10.0.28000.1836 (exc) |
| microsoft | windows_11_26h1 | to 10.0.28000.1836 (exc) |
| microsoft | windows_server_2016 | to 10.0.14393.9060 (exc) |
| microsoft | windows_server_2019 | to 10.0.17763.8644 (exc) |
| microsoft | windows_server_2022 | to 10.0.20348.5020 (exc) |
| microsoft | windows_server_2022_23h2 | to 10.0.25398.2274 (exc) |
| microsoft | windows_server_2025 | to 10.0.26100.32690 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a use after free issue in the Windows Ancillary Function Driver for WinSock. It allows an authorized attacker to elevate their privileges locally on the affected system.
How can this vulnerability impact me? :
The vulnerability can allow an attacker who already has some level of access to the system to increase their privileges. This means they could gain higher-level permissions, potentially leading to greater control over the system and the ability to perform unauthorized actions.
What immediate steps should I take to mitigate this vulnerability?
This vulnerability allows an authorized attacker to elevate privileges locally via a use after free in the Windows Ancillary Function Driver for WinSock.
To mitigate this vulnerability, apply the security updates provided by Microsoft as soon as possible.