CVE-2026-45638

Analyzed Analyzed - Analysis Complete

Use After Free in Windows Ancillary Function Driver for WinSock

Publication date: 2026-06-09

Last updated on: 2026-06-11

Assigner: Microsoft Corporation

Description

Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-06-09

Last Modified

2026-06-11

Generated

2026-06-30

AI Q&A

2026-06-09

EPSS Evaluated

2026-06-28

NVD

CVE-2026-45638

EUVD

EUVD-2026-35564

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2012	r2
microsoft	windows_server_2012	*
microsoft	windows_10_1607	to 10.0.14393.9234 (exc)
microsoft	windows_10_1607	to 10.0.14393.9234 (exc)
microsoft	windows_10_1809	to 10.0.17763.8880 (exc)
microsoft	windows_10_1809	to 10.0.17763.8880 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7417 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7417 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7417 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7417 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7417 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7417 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7219 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7219 (exc)
microsoft	windows_11_24h2	to 10.0.26100.8655 (exc)
microsoft	windows_11_24h2	to 10.0.26100.8655 (exc)
microsoft	windows_11_25h2	to 10.0.26200.8655 (exc)
microsoft	windows_11_25h2	to 10.0.26200.8655 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2269 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2269 (exc)
microsoft	windows_server_2016	to 10.0.14393.9234 (exc)
microsoft	windows_server_2019	to 10.0.17763.8880 (exc)
microsoft	windows_server_2022	to 10.0.20348.5256 (exc)
microsoft	windows_server_2025	to 10.0.26100.32995 (exc)

Helpful Resources

Exploitability

CWE

KEV

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().

Attack-Flow Graph

Executive Summary

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.

Impact Analysis

The impact of this vulnerability is that an attacker who already has some level of access to the system can exploit it to gain higher privileges. This can lead to full control over the affected system, allowing the attacker to perform actions that require elevated permissions.

Mitigation Strategies

To mitigate this vulnerability, it is important to apply the security updates provided by Microsoft as soon as they are available.

Since the vulnerability allows local privilege escalation via the Windows Ancillary Function Driver for WinSock, limiting local user access and ensuring systems are updated can reduce risk.

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