PT-2026-40214 · Microsoft · Windows Tcp/Ip+1

Published 2026-05-12 · Updated 2026-05-12 · CVE-2026-40399

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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

Description A stack-based buffer overflow in Windows TCP/IP allows an authorized attacker to perform a local privilege escalation, enabling them to gain SYSTEM-level permissions.

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

Stack Overflow

Weakness Enumeration

CWE-121

Related Identifiers

BDU:2026-07122

CVE-2026-40399

Affected Products

Windows

Windows Tcp/Ip

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-40399 · Security Note
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40399 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-40399 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-40399 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-07122 · Security Note
• https://twitter.com/windowsforum/status/2054285894178209932 · Twitter Post