Description
Windows TCP/IP Denial of Service Vulnerability
Published: 2026-05-12
Score: 7.1 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability targets the Windows TCP/IP stack, resulting in a denial of service that interrupts network communication on the affected machine. The issue can bring a system offline until a restart or update restores the networking component.

Affected Systems

Affected Windows products include Windows 10 versions 1607, 1809, 21H2, 22H2; Windows 11 versions 23H2, 24H2, 25H2, 26H1; and Windows Server releases from Server 2012 through Server 2025, including standard and Server Core installations.

Risk and Exploitability

The CVSS score is 7.1, indicating a high‑medium severity for denial of service. The EPSS score is <1%, suggesting a very low, but non‑zero, probability of exploitation; the vulnerability is not listed in CISA KEV. Based on the description, it is inferred that the attack may require local access, although remote exploitation is not documented.

Generated by OpenCVE AI on June 1, 2026 at 21:51 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the Microsoft security update for CVE-2026-40401 to all affected Windows releases (see https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40401).
  • If the update cannot be applied immediately, isolate vulnerable systems by limiting high‑risk TCP traffic and monitor for disruptions in networking behavior.
  • Maintain a regular patch management cycle to ensure systems remain up to date with this and related stack updates.

Generated by OpenCVE AI on June 1, 2026 at 21:51 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Mon, 01 Jun 2026 19:00:00 +0000

Type Values Removed Values Added
Description Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service locally. Windows TCP/IP Denial of Service Vulnerability

Fri, 15 May 2026 15:30:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft windows Server 2022 23h2
CPEs cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
Vendors & Products Microsoft windows Server 2022 23h2

Wed, 13 May 2026 11:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 13 May 2026 10:00:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 22h3
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012 (server Core Installation)
Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2022, 23h2 Edition (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Vendors & Products Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 22h3
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012 (server Core Installation)
Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2022, 23h2 Edition (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)

Tue, 12 May 2026 17:30:00 +0000

Type Values Removed Values Added
Description Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service locally.
Title Windows TCP/IP Denial of Service Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
Weaknesses CWE-476
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_23h2:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C'}

Subscriptions

Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 21h2 Windows 10 22h2 Windows 10 22h2 Windows 11 22h3 Windows 11 23h2 Windows 11 23h2 Windows 11 24h2 Windows 11 24h2 Windows 11 25h2 Windows 11 25h2 Windows 11 26h1 Windows 11 26h1 Windows Server 2012 Windows Server 2012 (server Core Installation) Windows Server 2012 R2 Windows Server 2012 R2 Windows Server 2012 R2 (server Core Installation) Windows Server 2016 Windows Server 2016 (server Core Installation) Windows Server 2019 Windows Server 2019 (server Core Installation) Windows Server 2022 Windows Server 2022, 23h2 Edition (server Core Installation) Windows Server 2022 23h2 Windows Server 2025 Windows Server 2025 (server Core Installation) Windows Server 23h2
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-06-01T23:44:47.386Z

Reserved: 2026-04-13T00:27:50.798Z

Link: CVE-2026-40401

cve-icon Vulnrichment

Updated: 2026-05-13T10:19:37.417Z

cve-icon NVD

Status : Modified

Published: 2026-05-12T18:17:17.820

Modified: 2026-06-01T19:16:36.983

Link: CVE-2026-40401

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-01T22:00:14Z

Weaknesses