CVE-2026-40401: Windows TCP/IP Denial of Service Vulnerability
Windows TCP/IP Denial of Service Vulnerability
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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Fixed in 6.3.9600.23181Patch KB5087471 - Upgrade
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Fixed in 6.2.9200.26079Patch KB5087470 - Upgrade
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Fixed in 10.0.14393.9140Patch KB5087537 - Upgrade
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Fixed in 10.0.28000.2113Patch KB5089548 - Upgrade
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Fixed in 10.0.26200.8457Fixed in 10.0.26200.8390Patch KB5089466 - Upgrade
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Fixed in 10.0.25398.2330Patch KB5087541 - Upgrade
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Fixed in 10.0.26100.8457Fixed in 10.0.26100.8390Patch KB5089466 - Upgrade
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Fixed in 10.0.22631.7219Patch KB5093998 - Upgrade
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Fixed in 10.0.26100.32860Fixed in 10.0.26100.32772Patch KB5087423 - Upgrade
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Fixed in 10.0.22631.7079Patch KB5087420 - Upgrade
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Fixed in 10.0.20348.5139Fixed in 10.0.20348.5074Patch KB5087424 - Upgrade
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Fixed in 10.0.19044.7291Patch KB5087544 - Upgrade
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Fixed in 10.0.19045.7417Patch KB5094127 - Upgrade
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Fixed in 10.0.17763.8755Patch KB5087538
Event History
Frequently Asked Questions
What is the severity of CVE-2026-40401?
CVE-2026-40401 is a critical vulnerability that allows an unauthorized attacker to cause a denial of service on affected systems.
How do I fix CVE-2026-40401?
To fix CVE-2026-40401, apply the latest security patches provided by Microsoft for your affected Windows operating system.
What are the affected versions for CVE-2026-40401?
CVE-2026-40401 affects multiple versions of Microsoft Windows, including Windows 10, Windows 11, and several Windows Server versions.
What type of vulnerability is CVE-2026-40401?
CVE-2026-40401 is classified as a denial of service vulnerability caused by a null pointer dereference in the Windows TCP/IP stack.
Can CVE-2026-40401 be exploited remotely?
CVE-2026-40401 requires local access to exploit, meaning an attacker must have access to the affected system to trigger the vulnerability.