CVE-2026-40405

Windows TCP/IP Denial of Service Vulnerability

State: Published
Severity: 7.5 High
Published: May 12, 2026
Updated: Aug 10, 2026
Reserved: Apr 13, 2026

Description

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

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-476 NULL Pointer Dereference

Affected Products

Product	Versions
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.8457Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.8457Affected
Windows 11 version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.2113Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.32860Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.32860Affected

References

Windows TCP/IP Denial of Service Vulnerabilityvendor-advisorypatch

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.