CVE-2026-56648

Analyzed Analyzed - Analysis Complete

Windows NFS Race Condition Privilege Escalation

Publication date: 2026-07-14

Last updated on: 2026-07-22

Assigner: Microsoft Corporation

Description

Time-of-check time-of-use (toctou) race condition in Windows Network File System allows an authorized attacker to elevate privileges over a network.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-14

Last Modified

2026-07-22

Generated

2026-08-04

AI Q&A

2026-07-15

EPSS Evaluated

2026-08-02

NVD

CVE-2026-56648

EUVD

EUVD-2026-44260

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2012	r2
microsoft	windows_server_2012	*
microsoft	windows_11_26h1	to 10.0.28000.2269 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2269 (exc)
microsoft	windows_10_1607	to 10.0.14393.9339 (exc)
microsoft	windows_10_1607	to 10.0.14393.9339 (exc)
microsoft	windows_10_1809	to 10.0.17763.9020 (exc)
microsoft	windows_10_1809	to 10.0.17763.9020 (exc)
microsoft	windows_11_24h2	to 10.0.26100.8875 (exc)
microsoft	windows_11_24h2	to 10.0.26100.8875 (exc)
microsoft	windows_server_2025	to 10.0.26100.33158 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7548 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7548 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7548 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7548 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7548 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7548 (exc)
microsoft	windows_11_25h2	to 10.0.26200.8875 (exc)
microsoft	windows_11_25h2	to 10.0.26200.8875 (exc)
microsoft	windows_server_2022	to 10.0.20348.5386 (exc)
microsoft	windows_server_2016	to 10.0.14393.9339 (exc)
microsoft	windows_server_2019	to 10.0.17763.9020 (exc)

Helpful Resources

Exploitability

CWE

KEV

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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

Executive Summary

This is a time-of-check time-of-use (toctou) race condition in Windows Network File System. It allows an authorized attacker to elevate their privileges over a network by exploiting a timing issue in the system.

Impact Analysis

An attacker could gain higher privileges on your system through the network, potentially allowing them to access sensitive data or perform unauthorized actions.

Compliance Impact

This vulnerability allows privilege escalation over a network, which could lead to unauthorized access to sensitive data. This may violate compliance requirements for data protection standards like GDPR and HIPAA by enabling unauthorized access to personal or health information.

Mitigation Strategies

Apply the latest security updates from Microsoft for Windows Network File System to patch the TOCTOU race condition. Monitor Microsoft's update guide for specific patches and install them promptly.

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