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.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2026-42904- CVSS 3.1
- 9.6 Critical
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 - Weakness
- CWE-122
- Updated
- 2026-11-11
EUVDEUVD-2026-35593
Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.
- Record
EUVD-2026-35593- CVSS 3.1
- 9.6 Critical
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 - Updated
- 2026-11-11
GitHub AdvisoriesGHSA-3f78-xrf3-9xc8
Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate...
Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.
- Record
GHSA-3f78-xrf3-9xc8- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
NVD
Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.
- Record
CVE-2026-42904- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
Affected products
- microsoft windows 10 version 21h2
- microsoft windows 10 version 22h2
- microsoft windows 11 version 23h2
- microsoft windows 11 version 24h2
- microsoft windows 11 version 25h2
- microsoft windows 11 version 26h1
- microsoft windows server 2022
- microsoft windows server 2025
- microsoft windows server 2025 (server core installation)
- microsoft windows 10 21h2
- microsoft windows 10 22h2
- microsoft windows 11 23h2
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History
| Recorded | Changed | Sources |
|---|---|---|
| facts | EUVD | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-42904 is a critical vulnerability (CVSS 9.6) in Microsoft Windows 10 Version 21h2, published June 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.44%, the 38th percentile. No source names a fixed version.