CVE-2026-45603

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:
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Meta Information

Published

2026-06-09

Last Modified

2026-06-11

Generated

2026-06-30

AI Q&A

2026-06-10

EPSS Evaluated

2026-06-28

NVD

CVE-2026-45603

EUVD

EUVD-2026-35565

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-362	The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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

Mitigation Strategies

To mitigate this vulnerability, apply the security updates provided by Microsoft as soon as possible to patch the Windows Ancillary Function Driver for WinSock.

Ensure that only authorized users have local access to the affected systems, as the vulnerability requires local privilege escalation.

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

An attacker who is already authorized on the system can exploit this vulnerability to gain higher privileges. This means they could perform actions that require elevated permissions, potentially compromising system integrity, confidentiality, and availability.

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