---
id: CVE-2026-42904
title: Windows TCP/IP Elevation of Privilege Vulnerability
summary: >-
  Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker
  to elevate privileges over an adjacent network.
severity: critical
cvss: 9.6
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C'
cvssSource: cna
cwe:
  - CWE-122
vendor: Microsoft
product: Windows 10 Version 21H2
affected:
  - windows_10_version_21h2 >= 10.0.19044.0 < 10.0.19044.7417
  - windows_10_version_22h2 >= 10.0.19045.0 < 10.0.19045.7417
  - windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7219
  - windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7219
  - windows_11_version_24h2 >= 10.0.26100.0 < 10.0.26100.8655
  - windows_11_version_25h2 >= 10.0.26200.0 < 10.0.26200.8655
  - windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.2269
  - windows_server_2022 >= 10.0.20348.0 < 10.0.20348.5256
  - windows_server_2025 >= 10.0.26100.0 < 10.0.26100.32995
  - >-
    windows_server_2025_server_core_installation >= 10.0.26100.0 <
    10.0.26100.32995
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-06-10T03:55:38.381186Z'
published: '2026-06-09'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T13:44:53.088Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-42904'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42904'
    label: Windows TCP/IP Elevation of Privilege Vulnerability
tags:
  - cve.org
epss: 0.00535
epssPercentile: 0.4266
ingestedAt: '2026-09-24T14:44:21.379Z'
---

## Overview

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

## Affected

- `windows_10_version_21h2 >= 10.0.19044.0 < 10.0.19044.7417`
- `windows_10_version_22h2 >= 10.0.19045.0 < 10.0.19045.7417`
- `windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7219`
- `windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7219`
- `windows_11_version_24h2 >= 10.0.26100.0 < 10.0.26100.8655`
- `windows_11_version_25h2 >= 10.0.26200.0 < 10.0.26200.8655`
- `windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.2269`
- `windows_server_2022 >= 10.0.20348.0 < 10.0.20348.5256`
- `windows_server_2025 >= 10.0.26100.0 < 10.0.26100.32995`
- `windows_server_2025_server_core_installation >= 10.0.26100.0 < 10.0.26100.32995`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.