PT-2026-40218 · Microsoft · Windows Tcp/Ip+1

Published 2026-05-12 · Updated 2026-05-12 · CVE-2026-40405

Positive Technologies (AI Summary)

CVSS v2.0

7.8

High

Base vector

AV:N/AC:L/Au:N/C:N/I:N/A:C

Name of the Vulnerable Software and Affected Versions Windows TCP/IP (affected versions not specified)

Description A null pointer dereference in the Windows TCP/IP stack allows an unauthorized attacker to cause a denial of service over a network, leading to system instability or crashes.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

RCE

DoS

NULL Pointer Dereference

Weakness Enumeration

CWE-476

Related Identifiers

BDU:2026-06801

CVE-2026-40405

Affected Products

Windows

Windows Tcp/Ip

References · 6

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40405 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-40405 · Security Note
• https://bdu.fstec.ru/vul/2026-06801 · Security Note
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-40405 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-40405 · Vendor Advisory
• https://twitter.com/windowsforum/status/2054286904728625553 · Twitter Post