Cyber Resilience

CVE-2026-40405

High

Published: 12 May 2026

Published
12 May 2026
Modified
15 May 2026
KEV Added
—
Patch
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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0015 35.2th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-40405 is a high-severity NULL Pointer Dereference (CWE-476) vulnerability in Microsoft Windows 11 24H2. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 35.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a network.

CWE(s)
CWE-476

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Why these techniques?

Null pointer dereference in network stack directly enables remote DoS via application/system exploitation.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2026-32071Same product: Microsoft Windows 11 24H2
CVE-2026-40401Same product: Microsoft Windows 11 24H2
CVE-2026-40413Same product: Microsoft Windows 11 24H2
CVE-2026-40414Same product: Microsoft Windows 11 24H2
CVE-2026-21525Same product: Microsoft Windows 11 24H2
CVE-2026-20875Same product: Microsoft Windows 11 24H2
CVE-2026-21243Same product: Microsoft Windows Server 2025
CVE-2025-21285Same product: Microsoft Windows 11 24H2
CVE-2026-33096Same product: Microsoft Windows 11 24H2
CVE-2026-25167Same product: Microsoft Windows 11 24H2

Affected Assets

microsoft
windows 11 24h2
≤ 10.0.26100.8390 · ≤ 10.0.26100.8390
microsoft
windows 11 25h2
≤ 10.0.26200.8390 · ≤ 10.0.26200.8390
microsoft
windows 11 26h1
≤ 10.0.28000.2113 · ≤ 10.0.28000.2113
microsoft
windows server 2025
≤ 10.0.26100.32772

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References