CVE-2026-40405: CWE-476: NULL Pointer Dereference in Microsoft Windows 11 Version 24H2
Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a network.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-40405) involves a null pointer dereference in the Windows TCP/IP implementation in Windows 11 Version 24H2 (build 10.0.26100.0). Exploitation can lead to denial of service by causing the affected system to crash or become unresponsive. The vulnerability has a CVSS 3.1 base score of 7.5, indicating high severity, with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to availability. Microsoft has released an official fix for this vulnerability.
Potential Impact
An attacker can remotely cause a denial of service condition on affected Windows 11 Version 24H2 systems by exploiting the null pointer dereference in the TCP/IP stack. This results in system crashes or unavailability, impacting service continuity. There is no confidentiality or integrity impact reported.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40405 to remediate this vulnerability.
CVE-2026-40405: CWE-476: NULL Pointer Dereference in Microsoft Windows 11 Version 24H2
Description
Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a network.
CVSS v3.1
Score 7.5high
Affected software
Microsoft
Windows 11 Version 24H2
Microsoft
Windows 11 Version 25H2
Microsoft
Windows 11 version 26H1
Microsoft
Windows Server 2025
Microsoft
Windows Server 2025 (Server Core installation)
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-40405) involves a null pointer dereference in the Windows TCP/IP implementation in Windows 11 Version 24H2 (build 10.0.26100.0). Exploitation can lead to denial of service by causing the affected system to crash or become unresponsive. The vulnerability has a CVSS 3.1 base score of 7.5, indicating high severity, with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to availability. Microsoft has released an official fix for this vulnerability.
Potential Impact
An attacker can remotely cause a denial of service condition on affected Windows 11 Version 24H2 systems by exploiting the null pointer dereference in the TCP/IP stack. This results in system crashes or unavailability, impacting service continuity. There is no confidentiality or integrity impact reported.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40405 to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-04-13T00:27:50.798Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40405","vendor":"Microsoft"}]
Threat ID: 6a036557cbff5d861008c9bb
Added to database: 05/12/2026, 17:37:27 UTC
Last enriched: 08/11/2026, 16:47:58 UTC
Last updated: 09/14/2026, 22:01:33 UTC
Views: 89
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