MSRC-CVE-2026-42904 — Windows TCP/IP Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

According to the CVSS metric, the attack vector is adjacent (AV:A). What does that mean for this vulnerability?
An authenticated attacker could exploit this vulnerability with LAN access.

Security updates
10.0.20348.5256 — https://support.microsoft.com/help/5094128
10.0.19044.7417 — https://support.microsoft.com/help/5094127
10.0.26100.32995 — https://support.microsoft.com/help/5094125
10.0.26200.8655 — https://support.microsoft.com/help/5094126
10.0.22631.7219 — https://support.microsoft.com/help/5093998
10.0.28000.2269 — https://support.microsoft.com/help/5095051

Vulnerabilities 1

Critical 9.6

CVE-2026-42904

Windows TCP/IP Elevation of Privilege Vulnerability

Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.

Microsoft Windows Server 2022 Windows 10 Version 21H2 Windows 10 Version 22H2 Windows

Jun 9, 2026

Revision history

2026-06-09 #1
Information published.

References

CVE-2026-42904 Windows TCP/IP Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42904
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss