CVE-2026-56648: Windows NFS Server Elevation of Privilege Vulnerability
Time-of-check time-of-use (toctou) race condition in Windows Network File System allows an authorized attacker to elevate privileges over a network.
Other sources
Windows NFS Server Elevation of Privilege Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.19045.7548Patch KB5099539 - Upgrade
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Fixed in 10.0.26100.33158Patch KB5099536 - Upgrade
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Fixed in 6.2.9200.26226Patch KB5099445 - Upgrade
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Fixed in 10.0.19044.7548Patch KB5099539 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.3.9600.23291Patch KB5099444 - Upgrade
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Fixed in 10.0.14393.9339Patch KB5099535 - Upgrade
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Fixed in 10.0.28000.2525Patch KB5101649 - Upgrade
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Fixed in 10.0.26100.8875Patch KB5101650 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5386Patch KB5099540 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.17763.9020Patch KB5099538 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26200.8875Patch KB5101650
Event History
Frequently Asked Questions
What level of access does an attacker need?
The attacker must be authorized and able to reach the target over the network. Exploitation has high attack complexity and does not require user interaction.
Which Windows releases are listed as affected?
The listed software includes Windows 10, Windows 10 21H2, Windows 10 22H2, Windows 11, Windows Server 2012, Windows Server 2016, Windows Server 2019, and Windows Server 2025.
What security impact could successful exploitation have?
Successful exploitation could allow privilege elevation and is rated as having high confidentiality, integrity, and availability impact.